Chemical and Pharmaceutical Bulletin
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β-Selective Glycosylation Using Axial-Rich and 2-O-Rhamnosylated Glucosyl Donors Controlled by the Protecting Pattern of the Second Sugar
Masafumi Bando, Yuri Kawasaki, Osamu Nagata, Yasunori Okada, Daiki Ikuta, Kazutada Ikeuchi , Hidetoshi Yamada
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Keywords: 2-O-ramnosylated glucose donor, β-selective glycosylation, axial-rich, bulky silyl group, protecting group effect
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2021 Volume 69 Issue 1 Pages 124-140

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Abstract

Herein, we describe two counterexamples of the previously reported β/α-selectivity of 96/4 for glycosylation using ethyl 2-O-[2,3,4-tris-O-tert-butyldimethylsilyl (TBS)-α-L-rhamnopyranosyl]-3,4,6-tris-O-TBS-thio-β-D-glucopyranoside as the glycosyl donor. Furthermore, we investigated the effects of protecting group on the rhamnose moieties in the glycosylation with cholestanol and revealed that β-selectivity originated from the two TBS groups at the 3-O and 4-O positions of rhamnose. In contrast, the TBS group at the 2-O position of rhamnose hampered the β-selectivity. Finally, the β/α-selectivity during the glycosylation was enhanced to ≥99/1. The results obtained herein suggest that the protecting groups on the sugar connected to the 2-O of a glycosyl donor with axial-rich conformation can control the stereoselectivity of glycosylation.

Introduction

2-O-α-L-Rhamnosyl-D-glucose (neohesperidose) is a common disaccharide present in plants, and it frequently forms β-glycosyl bonds with an aglycon, such as naringin or neohesperidin1,2) (Fig. 1a). These compounds exhibit various biological activities,3–7) and the novel glycosides of flavones,8–12) terpenes,13–17) and steroids18–22) are naturally occurring; therefore, they have attracted attentions of the pharmaceutical chemists. The synthesis of 2-O-α-L-rhamnosyl-β-O-glucosidic structure involves the rhamnosylation of 2-O in a glucosyl donor bearing an aglycon at the β-anomeric oxygen.23–27) The donor can be prepared with high β-stereoselectivity via the glycosylation of a glucosyl donor bearing a participating group,28) such as an acyl group, at the 2-O position with an aglycon. Another method involves the glycosylation of 2-O-rhamnosyl glucosyl donors with an aglycon.29–33) Although this method is more convergent for constructing disaccharides, stereoselectivity is inferior because of the absence of neighboring group participation.34) Therefore, addressing this disadvantage would enhance the use of direct glycosylation for the synthesis of natural products containing disaccharide moieties.

Fig. 1. a. Structures of Neohesperidose and Natural Products Containing Its Moiety; b. β-Selective Glycosylation Using the Conformational Lock Strategy; c. Development of β-Selective Glycosylation of Disaccharide 4 with Cholesterol

We have previously reported β-selective glycosylation using ethyl 6-O-pivaloyl-1-thio-2,3,4-tri-O-triisopropylsilyl (TIPS)-β-D-glucopyranoside (1) via the conformational lock strategy35–44) based on the steric bulk of silyl-protecting groups45) (Fig. 1b). The selectivity is rationalized to originate from the hindrance at the α-face of the reaction intermediate 2 by the 2-O-TIPS group, resulting in the β-selective attack by glycosyl acceptor to 2, thereby affording β-3 with high selectivity. This concept for inducing β-selectivity was expanded to the direct glycosylation of 2-O-rhamnosylated glucose donor 4 with cholesterol, affording β-glycoside 5 with high selectivity46) (Fig. 1c). Other donors that replaced the rhamnose moiety of 4 with a glucose and xylose moiety were also applied. The selectivity can be attributed to the steric bulk of the entire rhamnosyl moiety that arises due to the protection of three hydroxy groups with tert-butyldimethylsilyl (TBS) groups. However, subsequent studies have shown that this hypothesis is incorrect because the selectivity was found to vary with a change in the protecting pattern of the rhamnose moiety. Herein, the influence of the TBS groups on 2-O, 3-O, and 4-O in the rhamnose moiety during the glycosylation reaction of 4 was examined.

Results and Discussion

This study was inspired by the observation of the decreasing β-selectivity in the glycosylation of disaccharide donor 6 with cholesterol (Fig. 2a). The donor was prepared from known disaccharide 746) via the removal of three acetyl (Ac) groups followed by the protection of the released hydroxy groups with TBS groups. The glycosylation of 6 with cholesterol using methyl trifluoromethanesulfonate (MeOTf) as an activator of the ethylthio group45) and 2,6-lutidine as an acid scavenger over molecular sieves (Msv) 4A afforded the corresponding glycoside 8 in 45% yield as a 33/67 anomeric mixture, with the β-isomer as the major product. The α/β ratio was significantly lower than that obtained from the reaction using 4. The analysis of the 1H-NMR spectra of both triacetates, 9-α and 9-β, derived from the anomeric mixture of 8 confirmed their anomeric stereochemistry as either conformation of the glucose part was 4C1, while the coupling constants (J) of the anomeric proton of 9-α and 9-β were 3.7 and 7.6 Hz, respectively. It was predicted that the reduction of steric bulkiness on the 2-O of the rhamnose moiety in 6 decreased the stereoselectivity. Therefore, we envisioned glycosylation using disaccharide 10 that was furnished with a bulky tert-butyldiphenylsilyl (TBDPS) group on the O-2 of the rhamnose moiety (Fig. 2b).

Fig. 2. Counterexamples to the Previously Reported β-Selectivity

Donor 10 was synthesized via the glycosylation of ethyl 1-thioglycoside 11 with rhamnosyl 2,2,2-trichloroacetimidate (TCAI) 12 (Fig. 2b). Thioglycoside 11 was derived from 1347) in five steps. The selective pivaloylation of the primary alcohol of 13 afforded 14, where the 2-O was protected with a 2-(azidomethyl)benzoyl (AZMB) group.48) The removal of 1,2-dimethoxy-1,2-dimethyl-1,2-ethanediyl group via acidic hydrolysis afforded diol 15. The protection of 15 with 2,2,2-trichloroethoxycarbonyl (Troc) groups followed by the removal of AZMB group afforded 11. The preparation of 12 was achieved by starting the reaction with 16.49) The protection of the hydroxy group of 16 with a TBDPS group afforded 17, where the allyl group was removed via the catalytic migration of the double bond over (1,5-cyclooctadiene)bis(methyldiphenylphosphine)iridium(I) hexafluorophosphate after catalyst activation with H2,50) followed by 1-propenyl group removal via epoxidation.51) The trichloroacetimidation of the obtained compound 18 provided only the α-isomer of 12. A trimethylsilyl trifluoromethanesulfonate (TMSOTf)-mediated rhamnosylation of 11 using 12 afforded 19. The replacement of the two trichloroethoxycarbonyl (Troc) groups in 19 with TBS via exposure of 19 to Zn powder in acetic acid and the treatment of the obtained compound 20 with O-(TBS)benzanilide52) afforded 10 in 16% yield over three steps.

With the desired donor 10 in hand, the glycosylation was performed with cholesterol. However, similar reaction conditions that were used for the reaction of 6 to provide 8 afforded 21 with lower stereoselectivity (α/β = 44/56). This indicated that the stereoselectivity was significantly affected by the protecting pattern of the rhamnose moiety.

To determine the reason for the observed stereoselectivities in the reactions using disaccharides 4, 6, and 10, five additional disaccharides, 22a–e, were prepared. These disaccharides differed in the position and the number of the TBS and benzyl (Bn) groups on the rhamnose moiety (Fig. 3). The preparations involved the rhamnosylation of the glucose derivative 2353) with rhamnosyl TCAIs 24a–e. Among these compounds, 24a–c have been previously characterized.54–56) Rhamnosyl TCAI 24d was prepared from 2557) via a deallylation sequence, similar to the conversion of 17 into 18, followed by the trichloroacetimidation of 26. The compound 24e was synthesized using allyl α-L-rhamnoside 27.58) The regioselective formation of an anisylidene acetal between the 2-O and 3-O of 27 was followed by the protection of 4-O with a TBDPS group to afford 28. Subsequently, the treatment of 28 with diisobutylaluminum hydride (DIBAL) induced the reductive cleavage of the anisylidene acetal to afford the separable p-methoxybenzyl (PMB) ethers 29 and 30 in 77 and 22% yields, respectively. After the benzylation of 29, the displacement of the PMB and TBDPS groups in 31 with acetyl groups via three steps produced 32. Finally, similar to the transformation of 25 into 24d, 32 was converted into 24e. Each rhamnosylation of 23 using 24a–e proceeded in a highly α-selective manner to provide 34a–e in 50–90% yields. The successive removal of acetyl groups in 34a and the introduction of TBS groups to the generated hydroxy moieties afforded the desired disaccharide donors 22a–e.

Fig. 3. Syntheses of Novel Rhamnosyl TCAIs 24d, 24e, and Disaccharides 22a–e

The conformations of the glucopyranose and rhamnopyranose rings of 22a–d were confirmed to be in the twist boat and 1C4 forms, respectively, based on 1H-NMR spectral analyses (Table 1). The 1H- and 13C-NMR spectra of 22e showed broad signals that hindered the determination of the ring conformation. However, the similar 3JH1–H2 value of the glucose moiety and 22a–d, as well as the overlapped narrow signals of H3 and H5 suggested that the glucose moiety was in a twist-boat conformation.

Table 1. 3JH–H between Neighboring Protons on the Pyranose Rings of 22a–e in Acetone-d6
Compoundglc or rha3JH1–H2 (Hz)3JH2–H3 (Hz)3JH3–H4 (Hz)3JH4–H5 (Hz)
22aglc8.90.03.20.0
rha1.43.09.09.4
22bglc8.50.03.20.0
rha1.63.09.49.4
22cglc8.90.03.20.0
rha1.82.59.49.4
22dglc8.70.03.40.0
rha1.82.59.29.2
22eglc8.5Unanalyzablea)Unanalyzablea)Unanalyzablea)
rha1.6Unanalyzablea)Unanalyzablea)Unanalyzablea)

a) Due to signal broadening.

The reactions of the disaccharides 22a–e with cholestanol proceeded in a largely β-selective manner, affording the corresponding glycosides 35a–e (Fig. 4). For each reaction, 1.2 equivalents of cholestanol with respect to the disaccharide 22a–e were used in dichloromethane with 2 equivalents of 2,6-lutidine as an acid scavenger and 4 equivalents of MeOTf as an activator in the presence of Msv 4A. The table shown in Fig. 4 summarizes the yield and anomeric selectivity for each reaction. Each α/β-ratio was determined based on the 1H-NMR spectrum of each crude product. However, it was unclear whether the major isomers of 35a–e were β-isomers because the glucose conformations of 35a–e were twist boat. Therefore, the β-stereochemistries were confirmed by the fact that the JH1–H2 values of 36a–e were ≥7.6 Hz, wherein each glucose conformation was in the chair form. The preparation of 36a–e was achieved via the desilylation of the major isomers of 35a–e, followed by the acetylation of the newly generated free hydroxy groups.

Fig. 4. Glycosylation of 22a–e with Cholestanol

These results indicated that (1) the position of TBS groups on the rhamnose moiety influenced the glycosylation reaction stereoselectivity for 22 and (2) extremely high β-selectivity was observed when the TBS groups were present on the 3-O and 4-O positions of the rhamnose moiety. Thus, the β-selectivity obtained using 35e was significantly higher than those obtained using 35c and 35d. Herein, the noticeable synergistic effect of the two TBS groups is the most important observation. The results from the reaction of 22a and 22b providing 35a and 35b indicated that the TBS group at the 3-O or 4-O positions could individually exhibit β-selectivity, but both the selectivities were moderate. Comparing these results with the glycosylation using 10 (Fig. 2b) showed an apparent effect of the bulky silyl-protecting group on the 2-O position of the rhamnose moiety, which decreased the β-selectivity. Therefore, the stereoselectivity (α/β = 4/96) obtained using the reaction of 4 reported previously46) was due to the overlap of the synergistic effect of the TBS groups on the 3-O and 4-O positions and the adverse effect of the TBS group on the 2-O position. Undoubtedly, the axial-rich conformation of glucose is also important for high β-selective glycosylation.

Conclusion

Two counterexamples against the previously reported β/α-selective glycosylation of 96/4 for glycosylation using 2-O-rhamnosyl glucosyl donor 4 are provided herein. The two results obtained by the glycosylation using 6 and 10 have inspired the investigation of the precise effects of the rhamnose moiety protecting group during glycosylation. Each glycosylation reaction using disaccharides 22a–e, which varied in the protecting pattern of the rhamnose moiety, revealed that the two TBS groups at the 3-O and 4-O positions of the rhamnose moiety were crucial for inducing highly β-selective glycosylation of 4. The introduction of a bulky silyl group at the 2-O position of the rhamnose moiety decreased the stereoselectivity. Previously, the reason for the β-selectivity in the direct formation of 2-O-glycosylated glucosides was attributed exclusively to the steric hindrance caused by the axially oriented substituent at O-2 of the glucose moiety that inhibits the glycosyl acceptor approach from the glucose α-face. However, this study shows that in addition to the effect of the axial-rich conformation of the first sugar, the protecting pattern of the second sugar that is far from the reaction center also influences the β-selectivity. This observation underlines the drawbacks involved in the directly appliying the knowledge obtained from the monosaccharide synthesis to larger saccharides synthesis. In contrast, the control of the stereoselectivity during the glycosylation of disaccharides or larger molecules might be achieved by designing a protecting pattern for the second or more distant sugars. The results presented will contribute to guiding the synthesis of glycosides containing neohesperidose and other related moieties.

Experimental

General Information

All commercially available reagents were used without further purification. All moisture and air sensitive reactions were performed under a positive pressure of nitrogen. When necessary, the glassware was dried under reduced pressure by heating with a heat-gun, and solvents were distilled prior to use. The substrates were azeotropically dried if needed by evaporation of their acetonitrile, benzene, or toluene solution several times to remove trace water that may be contained to the substrate.

The reaction mixture was magnetically stirred. The reactions were monitored by TLC and mass spectra MS. Anhydrous MgSO4 was used to dry organic layers after extraction and was removed by filtration through a cotton pad. The filtrate was concentrated and subjected to further purification protocols if necessary. This sequence was represented as “the general drying procedure” in Experimental Section. Concentration was performed under reduced pressure.

TLC was performed on Merck precoated silica gel 60 F-254. Spots were visualized by exposure to UV light, or by immersion into a solution of 2% anisaldehyde, 5% H2SO4 in ethanol or a solution of 10% phosphomolybdic acid in ethanol followed by heating at approx. 200 °C. Column chromatography (CC) was performed on Merck silica gel 60 (70–230 mesh). The melting points were determined using a Yanagimoto micro-melting point apparatus and are uncorrected. Specific optical rotations were determined using a JASCO DIP-370 polarimeter with a 100 mm cell at 589 nm. IR spectra are recorded on a JASCO FT/IR-5300 instrument and the major absorbance bands are all reported in wavenumbers (cm−1). High-resolution (HR) MS were obtained on a JEOL JMS-700 spectrometer for electrospray ionization (ESI) and are reported in units of mass to charge.

NMR spectra were recorded on JEOL JNM-ECX-400 (or α-JEOL 400) instruments at 400 and 101 MHz for 1H- and 13C-NMR, respectively. Either TMS or residual proton of deuterated solvent was used as internal reference. The 1H-NMR data are indicated by chemical shifts (δ), with the multiplicity, the coupling constants, the number of protons, the assignments (only protons corresponding to glucose, rhamnose, and aglycon) in the parentheses. With respect to aglycon, the diagnostic protons were just recorded. The multiplicities are abbreviated as follows: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; and br, broad. The 13C-NMR data are reported as the chemical shifts (δ) with the hydrogen multiplicity obtained from the distortionless enhancement by polarization transfer (DEPT) spectra. The multiplicities are abbreviated as follows: s, C; d, CH; t, CH2; and q, CH3. When the number for carbon was more than one, the number was added in parentheses.

Additional Abbreviations list: agl = aglycon, Bu = butyl, Bz = benzoyl, Calcd = calculated, cod = 1,5-cyclooctadiene, DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene, DDQ = 2,3-dichloro-5,6-dicyano-p-benzoquinone, DMAP = 4-(dimethylamino)pyridine, DMF = dimethylformamide, Et = ethyl, EDCI = 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, glc = glucose, GPC = gel permeation chromatography; Me = methyl, m-CPBA = meta-chloroperoxybenzoic acid, NIS = N-iodosuccinimide, ODS = octadecylsilylated silica gel; Ph = phenyl, Piv = pivaloyl, PMP = para-methoxyphenyl, PPTS = pyridinium para-toluenesulfonate. Rf = retention factor, rha = rhamnose, r.t. = room temperature, TBAF = tetra-normal-butylammonium fluoride, Tf = trifluoromethanesulfonyl, TFA = trifluoroacetic acid, THF = tetrahydrofuran, TMEDA = tetramethylethylenediamine, Ts = para-toluenesulfonyl.

Synthetic Procedure

Ethyl 2-O-(2,3,4-Tri-O-Bn-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-1-thio-β-D-glucopyranoside (6)

To a solution of 746) (500 mg, 652 µmol) in MeOH (4 mL) and THF (2 mL) was added NaOMe (7.0 mg, 0.16 mmol). The mixture was stirred for 30 min at r.t. Addition of saturated aqueous NH4Cl (3 mL) quenched the reaction. The aqueous mixture was concentrated to remove MeOH and THF. The resulting aqueous mixture was extracted with EtOAc (40 mL). The EtOAc layer was successively washed with H2O and brine. The general drying procedure gave a crude product, which main content was triol. To the solution of the crude product in DMF (6.5 mL) were added 2,6-lutidine (943 mg, 8.80 mmol) and TBSOTf (517 mg, 1.96 mmol). The mixture was stirred for 5 min at 100 °C. After the mixture was cooled to r.t., the mixture was added additional TBSOTf (517 mg, 1.96 mmol) and stirred for 5 min at 100 °C; this process was repeated one more time. After addition of H2O (20 mL), the mixture was extracted with hexane. The combined hexane layer was successively washed with 1 M hydrochloric acid, saturated aqueous NaHCO3, and brine. After general drying procedure, the resulting mixture was purified by CC (SiO2 50 g, hexane/Et2O = 50/1 to 15/1) to give 6 (606 mg, 94% yield for 2 steps) as a white solid. Data for 6: mp 60.9–62.3 °C. [α]D22 −32.5 (c 1.02, CHCl3). IR (ZnSe) 3088, 3065, 3030, 2955, 2930, 2886, 2859, 1472, 1462, 1361, 1097, 837, 777 cm−1. 1H-NMR (400 MHz, CD2Cl2) δ: 7.37–7.25 (m, 15H), 4.95 (d, J = 1.4 Hz, 1H, rha-H1), 4.89 (d, J = 11.0 Hz, 1H), 4.75 (d, J = 12.1 Hz, 1H), 4.73 (d, J = 8.9 Hz, 1H, glc-H1), 4.68 (d, J = 12.1 Hz, 1H), 4.63 (d, J = 11.0 Hz, 1H), 4.61 (d, J = 12.1 Hz, 1H), 4.58 (d, J = 12.1 Hz, 1H), 4.12 (dq, J = 9.6, 6.2 Hz, 1H, rha-H5), 3.93 (ddd, J = 3.0, 0.6, 0.6 Hz, 1H, glc-H3), 3.84–3.80 (m, 2H, glc-H5, rha-H2), 3.79 (br d, J = 3.0 Hz, 1H, glc-H4), 3.77 (dd, J = 11.0, 3.7 Hz, 1H, glc-H6), 3.72 (dd, J = 11.0, 3.9 Hz, 1H, glc-H6), 3.71 (dd, J = 8.9, 0.6 Hz, 1H, glc-H2), 3.70 (dd, J = 9.6, 0.9 Hz, 1H, rha-H3), 3.58 (dd, J = 9.6, 9.6 Hz, 1H, rha-H4), 2.75–2.56 (m, 2H), 1.27 (d, J = 6.2 Hz, 3H, rha-H6), 1.26 (t, J = 7.6 Hz, 3H), 0.91 (s, 9H), 0.90 (s, 9H), 0.86 (s, 9H), 0.14 (s, 3H), 0.12 (s, 3H), 0.07 (s, 3H), 0.07 (s, 3H), 0.06 (s, 3H), 0.00 (s, 3H). 13C-NMR (101 MHz, acetone-d6) δ: 140.8 (s), 140.5 (s), 140.5 (s), 130.0 (d, 2C), 129.9 (d, 2C), 129.7 (d, 2C), 129.4 (d, 2C), 129.3 (d, 2C), 129.2 (d), 129.1 (d, 2C), 129.0 (d), 128.9 (d), 96.9 (d), 85.3 (d), 82.0 (d), 82.0 (d), 81.9 (d), 79.2 (d), 77.0 (d), 76.3 (t), 75.3 (d), 74.4 (t), 73.4 (t), 71.4 (d), 70.3 (d), 65.9 (t), 27.4 (q, 3C), 27.2 (q, 6C), 25.4 (t), 19.7 (s), 19.3 (s), 19.2 (s), 19.0 (q), 16.6 (q), −3.2 (q), −3.3 (q), −3.4 (q), −3.5 (q), −4.0 (q), −4.0 (q). HRMS m/z [M + Na]+ Calcd for C53H86O9SSi3Na 1005.5198. Found 1005.5183.

Cholesteryl 2-O-(2,3,4-Tri-O-Bn-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-D-glucopyranoside (8)

To a solution of 6 (75.9 mg, 77.2 µmol) and cholesterol (35.8 mg, 92.6 µmol) in CH2Cl2 (1.0 mL) were added Msv 4A (120 mg), 2,6-lutidine (16.5 mg, 154 µmol), and MeOTf (76 mg, 0.46 mmol). The mixture was stirred for 20 h at r.t. After addition of Et3N (0.5 mL) and hexane (2.0 mL), the mixture was filtered through a Celite pad to remove the Msv. The filtrate was concentrated. The resulting residue was purified by CC (SiO2 4.5 g, hexane/Et2O = 50/1 to 10/1) to give 8 (45.8 mg, 45% yield) as a 33/67 of α/β diastereomeric mixtures. The ratio was determined using a 1H-NMR spectrum based on the integral of the vinyl proton on the cholesteryl moiety of each diastereomers. Partial data for 8: 1H-NMR (400 MHz, CDCl3) δ: 5.33 (br d, J = 5.5 Hz, 0.33H, glc-H1 of the α-isomer), 5.20 (br d, J = 5.0 Hz, 0.67H, glc-H1 of the β-isomer).

Cholesteryl 3,4,6-Tri-O-Ac-2-O-(2,3,4-tri-O-Bn-α-L-rhamnopyranosyl)-D-glucopyranoside (9)

A mixture of 8 (87.1 mg, 66.6 µmol) in THF (1 mL) was added TBAF (1.0 M THF solution, 0.6 mL). The mixture was stirred for 4.5 h at r.t. To the solution were added pyridine (1.0 mL), Ac2O (0.5 mL), and DMAP (5.0 mg). The mixture was stirred for 30 min at r.t. After evaporation to remove THF, the mixture was diluted with EtOAc (40 mL). The solution was successively washed with 1 M hydrochloric acid, saturated aqueous NaHCO3, and brine. After the general drying procedure, the mixture was purified by CC (SiO2 3.0 g, hexane/EtOAc = 5/1 to 4/1) to give 9 (67.7 mg, 93% yield) as a mixture of diastereomers. A part of the mixture was separated by HPLC (column, YMC-R-SIL-5 250 × 4.6 mm; eluent, hexane/EtOAc = 7/2) to give each diastereomer in pure form. Data for 9-α (the minor diastereomer): colorless syrup. [α]D23 +4.6 (c 0.52, CHCl3). IR (ATR) 3065, 3029, 2929, 2855, 1749, 1496, 1455, 1365, 1258, 1219, 1087, 1075, 1027, 882, 802, 754, 697, 664 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.34–7.26 (m, 15H), 5.34 (dd, J = 9.6, 9.6 Hz, 1H, glc-H3), 5.33 (br s, 1H, agl-H6), 5.02 (d, J = 3.7 Hz, 1H, glc-H1), 4.93 (dd, J = 9.8, 9.6 Hz, 1H, glc-H4), 4.93 (d, J = 11.5 Hz, 1H), 4.80 (d, J = 1.8 Hz, 1H, rha-H1), 4.72 (d, J = 12.6 Hz, 1H), 4.67 (d, J = 12.6 Hz, 1H), 4.64–4.59 (m, 3H), 4.24 (dd, J = 12.6, 5.0 Hz, 1H, glc-H6), 4.10 (ddd, J = 9.8, 5.0, 2.3 Hz, glc-H5), 4.06 (dd, J = 12.6, 2.3 Hz, 1H, glc-H6), 3.80 (dd, J = 9.2, 3.0 Hz, 1H, rha-H3), 3.71 (dq, J = 9.2, 6.2 Hz, 1H, rha-H5), 3.66 (dd, J = 3.0, 1.8 Hz, 1H, rha-H2), 3.64 (dd, J = 9.6, 3.7 Hz, 1H, glc-H2), 3.59 (dd, J = 9.2, 9.2 Hz, 1H, rha-H4), 3.44–3.34 (m, 1H, agl-H3), 2.07 (s, 3H), 2.02 (s, 3H), 1.77 (s, 3H), 1.28 (d, J = 6.2 Hz, 3H, rha-H6), 0.99 (s, 3H, agl-H18 or H19), 0.93 (d, J = 6.6 Hz, 3H, agl-H21), 0.87 (d, J = 6.6 Hz, 3H, agl-H21), 0.87 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.68 (s, 3H, agl-H26 or H27). 13C-NMR (101 MHz, CDCl3) δ: 170.8 (s), 170.1 (s), 170.0 (s), 140.6 (s), 139.0 (s), 138.6 (s), 138.3 (s), 128.5 (d), 128.5 (d, 3C), 128.3 (d), 127.9 (d), 127.9 (d, 2C), 127.8 (d, 2C), 127.6 (d, 2C), 127.5 (d, 3C), 122.2 (d), 100.8 (d), 97.4 (d), 80.3 (d), 80.0 (d), 79.9 (d), 76.8 (d), 74.8 (t), 74.3 (d), 72.8 (t), 72.6 (t), 72.0 (d), 69.0 (d), 68.8 (d), 67.3 (d), 62.3 (t), 56.8 (d), 56.2 (d), 50.2 (d), 42.4 (s), 40.4 (t), 39.8 (t), 39.6 (t), 37.2 (t), 36.7 (s), 36.3 (t), 35.9 (d), 32.0 (t), 31.9 (d), 29.8 (t), 28.3 (t), 28.1 (d), 24.3 (t), 23.9 (t), 22.9 (q), 22.7 (q), 21.1 (t), 20.9 (q), 20.8 (q), 20.7 (q), 19.4 (q), 18.8 (q), 18.1 (q), 11.9 (q). HRMS m/z [M + Na]+ Calcd for C66H90O13Na 1113.6279. Found 1113.6249. Data for 9-β (the major diastereomer): colorless syrup. [α]D22 −11 (c 0.92, CHCl3). IR (ATR) 3065, 3022, 2936, 2867, 1742, 1496, 1454, 1365, 1258, 1216, 1085, 1076, 1037, 882, 800, 753, 697, 666 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.34–7.21 (m, 15H), 5.27 (br d, J = 4.8 Hz, 1H, agl-H6), 5.17 (dd, J = 9.6, 9.2 Hz, 1H, glc-H3), 4.95 (dd, J = 10.0, 9.6 Hz, 1H, glc-H4), 4.95 (d, J = 2.0 Hz, 1H, rha-H1), 4.92 (d, J = 10.8 Hz, 1H), 4.68 (s, 2H), 4.63 (d, J = 11.6 Hz, 1H), 4.57 (s, 2H), 4.47 (d, J = 7.6 Hz, 1H, glc-H1), 4.26 (dd, J = 12.4, 5.2 Hz, 1H, glc-H6), 4.16 (dq, J = 9.6, 6.4 Hz, 1H, rha-H5), 4.06 (dd, J = 12.4, 2.0 Hz, 1H, glc-H6), 3.77 (dd, J = 9.2, 3.2 Hz, 1H, rha-H3), 3.74 (dd, J = 9.2, 7.6 Hz, 1H, glc-H2), 3.70 (dd, J = 3.2, 2.0 Hz, 1H, rha-H2), 3.63 (ddd, J = 10.0, 5.2, 2.0 Hz, 1H, glc-H5), 3.58 (dd, J = 9.6, 9.2 Hz, 1H, rha-H4), 3.54 (m, 1H, agl-H3), 2.06 (s, 3H), 2.00 (s, 3H), 1.89 (s, 3H), 1.30 (d, J = 6.4 Hz, 3H, rha-H6), 0.92 (d, J = 6.4 Hz, 3H, agl-H21), 0.89 (s, 3H, agl-H19), 0.87 (d, J = 6.8 Hz, 3H, agl-H26 or H27), 0.87 (d, J = 6.8 Hz, 3H, agl-H26 or H27), 0.68 (s, 3H, agl-H17). 13C-NMR (101 MHz, CDCl3) δ: 170.8 (s), 170.1 (s), 169.7 (s), 140.3 (s), 139.0 (s), 138.6 (s), 138.3 (s), 128.5 (d, 2C), 128.4 (d, 2C), 128.2 (d, 2C), 127.9 (d, 2C), 127.8 (d), 127.7 (d, 2C), 127.6 (d, 2C), 127.5 (d), 127.4 (d), 122.2 (d), 99.8 (d), 98.4 (d), 80.6 (d), 79.9 (d), 79.5 (d), 75.7 (d), 75.1 (d), 75.0 (t), 74.6 (d), 72.9 (t), 72.2 (t), 71.5 (d), 68.9 (d), 68.4 (d), 62.3 (t), 56.8 (d), 56.2 (d), 50.2 (d), 42.4 (s), 39.8 (t), 39.6 (t), 38.4 (t), 37.3 (t), 36.8 (s), 36.3 (t), 35.9 (d), 32.1 (t), 31.9 (d), 29.5 (t), 28.3 (t), 28.1 (d), 24.4 (t), 23.9 (t), 22.9 (q), 22.7 (q), 21.1 (t), 20.9 (q), 20.8 (q), 20.7 (q), 19.2 (q), 18.8 (q), 18.0 (q), 11.9 (q). HRMS m/z [M + Na]+ Calcd for C66H90O13Na 1113.6279. Found 1113.6249.

Ethyl 3,4-O-[(1S,2S)-1,2-Dimethoxy-1,2-dimethyl-1,2-ethanediyl]-6-O-Piv-1-thio-β-D-glucopyranoside (14)

To a solution of 1347) (4.17 g, 11.8 mmol) in pyridine (120 mL) were added PivCl (2.85 g, 23.7 mmol) and DMAP (145 mg, 1.18 mmol). The mixture was stirred for 30 min at r.t. Addition of H2O (200 mL) quenched the reaction. The aqueous mixture was extracted with EtOAc. The organic layer was successively washed with 1 M hydrochloric acid, saturated aqueous NaHCO3, and H2O. After the general drying procedure, the mixture was purified by CC (SiO2 120 g, hexane/EtOAc = 4/1 to 2/1) to give 14 (4.95 g, 99% yield) as a pale brown syrup. Data for 14: [α]D22 +124 (c 1.80, CHCl3). IR (ZnSe) 3506, 2964, 1732, 1481, 1458, 1286, 1134, 1086, 1032, 927, 900, 850, 760, 615 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 4.43 (dd, J = 12.1, 2.2 Hz, 1H, glc-H6), 4.35 (d, J = 9.4 Hz, 1H, glc-H1), 4.05 (dd, J = 12.1, 5.5 Hz, 1H, glc-H6), 3.70 (dd, J = 9.6, 9.1 Hz, 1H, glc-H3), 3.68 (ddd, J = 9.6, 5.5, 2.2 Hz, 1H, glc-H5), 3.60 (dd, J = 9.6, 9.6 Hz, 1H, glc-H4), 3.54 (dd, J = 9.4, 9.1 Hz, 1H, glc-H2), 3.28 (s, 3H), 3.21 (s, 3H), 2.74–2.60 (m, 2H), 2.52 (br, 1H), 1.32 (s, 3H), 1.27 (t, J = 7.3 Hz, 3H), 1.26 (s, 3H), 1.16 (s, 9H). 13C-NMR (101 MHz, CDCl3) δ: 178.2 (s), 99.8 (s), 99.7 (s), 86.2 (d), 75.9 (d), 73.5 (d), 69.8 (d), 66.0 (d), 62.4 (t), 48.2 (q), 48.1 (q), 38.8 (s), 27.2 (q, 3C), 24.2 (t), 17.7 (q), 17.6 (q), 15.5 (q). HRMS m/z [M + Na]+ Calcd for C19H34O8SNa 445.1872. Found 445.1879.

Ethyl 2-O-AZMB-6-O-Piv-1-thio-β-D-glucopyranoside (15)

To a solution of 14 (1.77 g, 4.18 mmol) in CH2Cl2 (42 mL) were added 2-azidomethylbenzoic acid (1.11 g, 6.27 mmol), EDCI (2.40 g, 12.5 mmol), and DMAP (2.55 g, 20.9 mmol). The mixture was stirred for 45 h at r.t. Addition of 1 M aqueous H3PO4 (30 mL) quenched the reaction. The separated organic layer was successively washed with H2O and brine. After the general drying procedure, the mixture was purified by CC (SiO2 50 g, hexane/EtOAc = 10/1) to give a mixture whose main content was the 2-O-AZMB compound of 14. To a solution of the mixture in CH2Cl2 (42 mL) was added a mixture of TFA and H2O (10/1, 22 mL). The mixture was stirred for 20 min at r.t. Addition of saturated aqueous NaHCO3 quenched the reaction. The separated organic layer was successively washed with saturated aqueous NaHCO3, H2O, and brine. After the general drying procedure, the mixture was purified by CC (SiO2 60 g, hexane/EtOAc = 4/1 to 1/1) to give 15 (1.27 g, 65% yield for 2 steps) as a colorless syrup. Data for 15: [α]D23 −36.1 (c 1.03, CHCl3). IR (ZnSe) 3520, 2959, 2102, 1724, 1456, 1257, 1140, 1076, 617 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.98 (d, J = 7.8 Hz, 1H), 7.55 (t, J = 6.4 Hz, 1H), 7.45 (d, J = 7.5 Hz, 1H), 7.40 (t, J = 7.5 Hz, 1H), 5.07 (dd, J = 10.0, 9.1 Hz, 1H, glc-H2), 4.75 (s, 2H), 4.56 (d, J = 10.0 Hz, 1H, glc-H1), 4.37–4.36 (m, 2H, glc-H6), 3.78 (dd, J = 9.1, 8.9 Hz, 1H, glc-H3), 3.52 (ddd, J = 9.6, 3.6, 3.5 Hz, 1H, glc-H5), 3.46 (dd, J = 9.6, 8.9 Hz, 1H, glc-H4), 2.77–2.61 (m, 2H), 1.25 (t, J = 7.5 Hz, 3H), 1.20 (s, 9H). 13C-NMR (101 MHz, CDCl3) δ: 179.4 (s), 166.3 (s), 136.9 (s), 132.9 (d), 131.3 (d), 130.0 (d), 128.9 (s), 128.4 (d), 83.1 (d), 78.0 (d), 76.3 (d), 72.9 (d), 70.5 (d), 63.4 (t), 53.2 (t), 39.0 (s), 27.2 (q, 3C), 24.0 (t), 15.1 (q). HRMS m/z [M + Na]+ Calcd for C21H29N3O7SNa 490.1624. Found 490.1628.

Ethyl 6-O-Piv-3,4-di-O-Troc-1-thio-β-D-glucopyranoside (11)

To a solution of 15 (1.18 g, 2.54 mmol) in CH2Cl2 (25 mL) were added TMEDA (880 mg, 7.58 mmol) and TrocCl (1.28 g, 6.09 mmol) at 0 °C. The mixture was stirred for 30 min at 0 °C. Addition of H2O (20 mL) quenched the reaction. The separated organic layer was successively washed with H2O and brine. After the general drying procedure, the mixture was purified by CC (SiO2 30 g, hexane/EtOAc = 9/1) to give a mixture whose main content was the 3,4-di-O-Troc compound of 15. To a solution of the mixture in THF (23 mL) were added H2O (207 mg, 11.5 mmol) and Bu3P (1.39 g, 6.90 mmol). The mixture was stirred for 15 min at r.t. CH2Cl2 (50 mL) was then added to the mixture, and the separated organic layer was successively washed with saturated aqueous NaHCO3, H2O, and brine. After the general drying procedure, the mixture was purified by CC (SiO2 54 g, hexane/EtOAc = 15/1 to 10/1) to give 11 (1.10 g, 71% yield for 2 steps) as a colorless syrup. Data for 11: [α]D23 −10.6 (c 2.39, CHCl3). IR (ZnSe) 3450, 2968, 1774, 1732, 1481, 1450, 1284, 1257, 1161, 1028, 983, 819, 615 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 5.09 (dd, J = 9.6, 9.4 Hz, 1H, glc-H3), 5.01 (dd, J = 9.7, 9,6 Hz, 1H, glc-H4), 4.77 (s, 2H), 4.74 (s, 2H), 4.44 (d, J = 9.8 Hz, 1H, glc-H1), 4.27 (dd, J = 12.4, 2.3 Hz, 1H, glc-H6), 4.19 (dd, J = 12.4, 3.6 Hz, 1H, glc-H6), 3.80 (ddd, J = 9.7, 3.6, 2.3 Hz, 1H, glc-H5), 3.68 (dd, J = 9.8, 9.4 Hz, 1H, glc-H2), 2.78–2.64 (m, 2H), 1.31 (t, J = 7.5 Hz, 3H), 1.19 (s, 9H). 13C-NMR (101 MHz, CDCl3) δ: 178.0 (s), 153.8 (s), 153.1 (s), 94.2 (s), 94.1 (s), 86.1 (d), 80.3 (d), 77.1 (t, 2C), 75.6 (d), 72.8 (d), 70.9 (d), 61.9 (t), 38.9 (s), 27.2 (q, 3C), 24.5 (t), 15.5 (q). HRMS m/z [M + Na]+ Calcd for C19H26Cl6O10SNa 678.9276. Found 678.9244.

Allyl 3,4-Di-O-Bz-2-O-TBDPS-α-L-rhamnopyranoside (17)

To a solution of 1649) (2.30 g, 5.58 mmol) in DMF (20 mL) were added 2,6-lutidine (1.62 g, 15.2 mmol) and TBDPSOTf (3.92 g, 10.1 mmol). The mixture was stirred at r.t. for 2 h. Addition of H2O (20 mL) quenched the reaction. The aqueous mixture was extracted with EtOAc. The organic layer was successively washed with 1 M hydrochloric acid, saturated aqueous NaHCO3, and brine. After the general drying procedure, the mixture was purified by CC, initially on SiO2 (70 g, hexane/EtOAc = 20/1 to 2/1), and then on ODS (70 g, MeOH/H2O = 5/1 to 1/0) to give 17 (2.19 g, 60% yield) as a white powder. Data for 17: mp 96–98 °C. [α]D23 −22.8 (c 3.21, CHCl3). IR (ZnSe) 3072, 2934, 2858, 1728, 1452, 1427, 1277, 1111, 1070, 1028, 837, 740, 707, 609 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.89–6.91 (m, 20H), 5.77 (dd, J = 10.1, 10.0 Hz, 1H, rha-H4), 5.61 (dddd, J = 17.1, 10.8, 8.2, 6.1 Hz, 1H), 5.49 (dd, J = 10.1 Hz, 3.0 Hz, 1H, rha-H3), 5.05 (dd, J = 17.1, 1.6 Hz, 1H), 4.98 (dd, J = 10.8, 1.6 Hz, 1H), 4.44 (d, J = 1.8 Hz, 1H, rha-H1), 4.20 (dd, J = 3.0, 1.8 Hz, 1H, rha-H2), 4.00 (dd, J = 10.0, 6.2 Hz, 1H, rha-H5), 3.97 (dd, J = 10.8, 8.2 Hz, 1H), 3.72 (dd, J = 10.8, 6.1 Hz, 1H), 1.27 (d, J = 6.2 Hz, 3H, rha-H6), 1.03 (s, 9H). 13C-NMR (101 MHz, CDCl3) δ: 165.9 (s), 165.9 (s), 136.0 (d, 2C), 135.9 (d, 2C), 133.6 (d), 133.6 (s), 133.5 (s), 133.1 (d), 133.0 (d), 132.7 (s), 130.0 (d), 129.9 (d, 2C), 129.7 (d, 3C), 128.4 (d, 2C), 128.3 (d, 2C), 127.8 (d, 2C), 127.5 (d, 2C), 117.5 (t), 98.6 (d), 72.5 (d), 71.9 (d), 71.1 (d), 68.1 (t), 67.2 (d), 26.9 (q, 3C), 19.4 (s), 17.9 (q). HRMS m/z [M + Na]+ Calcd for C39H42O7SiNa 673.2597. Found 673.2603.

3,4-Di-O-Bz-2-O-TBDPS-L-rhamnopyranose (18)

To a solution of 17 (1.20 g, 1.84 mmol) in THF (18 mL) was added Ir[(cod)(MePh2P)]PF6 (78.0 mg, 92.2 µmol). Under H2 atmosphere, the mixture was stirred for 30 s to give yellow solution. At this point, the atmosphere of the reaction was changed to N2 gas, and the mixture was stirred for 2 h at r.t. To the mixture were added H2O (1.8 mL) and m-CPBA (1.27 g, 7.35 mmol), and the mixture was stirred for 18 h at r.t. Addition of aqueous Na2S2O3 (10%, 10 mL) and saturated aqueous NaHCO3 (10 mL) quenched the reaction. The aqueous mixture was extracted with EtOAc. The combined organic layer was successively washed with saturated aqueous NaHCO3, H2O, and brine. After the general drying procedure, the mixture was purified by CC (SiO2 36 g, hexane/EtOAc = 10/1) to give 18 (1.05 g, 93%, β/α = 95/5) as a white powder. Partial data for 18: IR (ZnSe) 3452 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 5.24 (br d, J = 1.4 Hz, β-isomer, rha-H1), 5.01 (br d, J = 1.7 Hz, α-isomer, rha-H1). HRMS m/z [M + Na]+ Calcd for C36H38O7SiNa 633.2284. Found 633.2267.

3,4-Di-O-Bz-2-O-TBDPS-α-L-rhamnosyl TCAI (12)

To a stirred solution of 18 in (CH2Cl)2 (26 mL) were added DBU (200 mg, 1.32 mmol) and Cl3CCN (1.14 g, 7.89 mmol). The mixture was stirred for 3 h at r.t. After evaporation to remove (CH2Cl)2, the resulting residue was purified by CC (SiO2 48 g, hexane/EtOAc = 20/1) to give 12 (1.51 g, 76% yield) as a white powder. Data for 12: mp 168–170 °C. [α]D23 −18.9 (c 2.35, CHCl3). IR (ZnSe) 3342, 3072, 2934, 1730, 1674, 1602, 1452, 1427, 1273, 1109, 1068, 1028, 839, 796, 758, 707 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 8.38 (s, 1H), 7.90–6.97 (m, 20H), 5.95 (d, J = 2.2 Hz, 1H, rha-H1), 5.89 (dd, J = 10.0, 10.0 Hz, 1H, rha-H4), 5.48 (dd, J = 10.0, 3.0 Hz, 1H, rha-H3), 4.37 (dd, J = 3.0, 2.2 Hz, 1H, rha-H2), 4.19 (dq, J = 10.0, 6.2 Hz, 1H, rha-H5), 1.33 (d, J = 6.2 Hz, 3H, rha-H6), 1.06 (s, 9H). 13C-NMR (101 MHz, CDCl3) δ: 165.9 (s), 165.8 (s), 160.3 (s), 136.0 (d, 4C), 133.3 (d), 133.2 (d), 132.9 (s), 132.3 (s), 130.2 (d), 130.0 (d, 2C), 129.9 (d), 129.8 (d, 2C), 129.5 (s), 129.4 (s), 128.5 (d, 2C), 128.3 (d, 2C), 127.9 (d, 2C), 127.6 (d, 2C), 97.3 (d), 91.0 (s), 72.2 (d), 71.1 (d), 70.0 (d), 69.7 (d), 26.9 (q, 3C), 19.4 (s), 18.1 (q). HRMS m/z [M + Na]+ Calcd for C38H38Cl3NO7SiNa 776.1381. Found 776.1414.

Ethyl 2-O-(3,4-Di-O-Bz-2-O-TBDPS-α-L-rhamnopyranosyl)-3,4-di-O-TBS-6-O-Piv-1-thio-β-D-glucopyranoside (10)

To a solution of 11 (634 mg, 962 µmol) and 12 (1.09 g, 1.44 mmol) in CH2Cl2 (36 mL) were added Msv 4A (1.70 g) and TMSOTf (42.7 mg, 192 µmol). The mixture was stirred for 1 h at r.t. Addition of saturated aqueous NaHCO3 (20 mL) quenched the reaction. The aqueous mixture was extracted with CH2Cl2. The combined organic layer was washed with brine. After the general drying procedure, the mixture was separated by CC (SiO2 48 g, hexane/EtOAc = 10/1) to give a mixture containing 19 as the major product. To a solution of impure 19 in MeOH (3.0 mL) were added powdered zinc (188 mg, 2.88 mmol) and AcOH (0.3 mL). The mixture was stirred for 4.5 h at r.t. Addition of aqueous saturated NaHCO3 (20 mL) quenched the reaction. The aqueous mixture was concentrated under reduced pressure to remove MeOH and H2O. The resulting residue was dissolved in EtOAc using sonicator, and the unsolved component was removed by filtration through a Celite pad. The filtrate was concentrated and the resulting residue was purified by CC (SiO2 20 g, hexane/EtOAc = 10/1 to 5/1) to give a mixture containing 20 as the major product. To a solution of impure 20 in DMF (1.8 mL) were added O-(TBS)benzanilide (332 mg, 1.07 mmol) and PPTS (61.0 mg, 266 µmol). The mixture was stirred for 4.5 h at 100 °C. After the mixture was cooled to r.t., to this was added H2O (10 mL). The aqueous mixture was extracted with EtOAc. The combined organic layer was successively washed with saturated aqueous NaHCO3, H2O, and brine. After the general drying procedure, the mixture was purified by CC (SiO2 10 g, hexane/EtOAc = 20/1) and a further purification using HPLC (column, Develosil ODS-HG5; eluent, MeOH/H2O = 20/1) to give 10 (141 mg, 16% for 3 steps) as a white powder. Data for 10: mp 141–145 °C. [α]D22 −29 (c 0.55, CHCl3). IR (ZnSe) 2957, 2932, 2858, 1732, 1602, 1471, 1277, 1155, 1111, 1068, 1028, 835, 777, 709, 607 cm−1. 1H-NMR (400 MHz, acetone-d6) δ: 7.95 (d, J = 7.3 Hz, 2H), 7.70 (d, J = 7.3 Hz, 2H), 7.62 (d, J = 7.6 Hz, 2H), 7.59 (d, J = 7.3 Hz, 2H), 7.47 (dd, J = 7.6, 7.3 Hz, 1H), 7.42 (dd, J = 8.1, 7.3 Hz, 1H), 7.37–7.12 (m, 10H), 5.89 (dd, J = 10.1, 9.9 Hz, 1H, rha-H4), 5.57 (dd, J = 10.1, 2.7 Hz, 1H, rha-H3), 4.91 (d, J = 1.0 Hz, 1H, rha-H1), 4.88 (d, J = 8.7 Hz, 1H, glc-H1), 4.59 (dq, J = 9.9, 6.2 Hz, 1H, rha-H5), 4.23 (dd, J = 11.0, 6.9 Hz, 1H, glc-H6), 4.19 (br s, 1H, rha-H2), 4.15 (dd, J = 11.0, 6.9 Hz, 1H, glc-H6), 3.95 (dd, J = 6.9, 6.9 Hz, 1H, glc-H5), 3.76 (br d, J = 3.7 Hz, 1H, glc-H3), 3.73 (d, J = 8.7 Hz, 1H, glc-H2), 3.64 (d, J = 3.7 Hz, 1H, glc-H4), 2.81–2.64 (m, 2H), 1.34 (d, J = 6.2 Hz, 3H, rha-H6), 1.33 (t, J = 7.2 Hz, 3H), 1.20 (s, 9H), 1.09 (s, 9H), 0.85 (s, 9H), 0.76 (s, 9H), 0.01 (s, 3H), −0.03 (s, 3H), −0.05 (s, 3H), −0.17 (s, 3H). 13C-NMR (101 MHz, acetone-d6) δ: 178.7 (s), 167.1 (s), 166.6 (s), 137.5 (d, 4C), 134.9 (d), 134.7 (d), 134.4 (s), 134.2 (s), 131.8 (d), 131.6 (d), 131.4 (s), 131.3 (s), 131.1 (d, 2C), 131.0 (d, 2C), 130.2 (d, 2C), 129.9 (d, 2C), 129.6 (d, 2C), 129.4 (d, 2C), 98.5 (d), 82.2 (d), 81.9 (d), 79.4 (d), 74.7 (d), 73.6 (d), 73.5 (d), 73.5 (d), 71.4 (d), 69.3 (d), 66.7 (t), 40.0 (s), 28.2 (q, 3C), 28.1 (q, 3C), 26.9 (q, 3C), 26.8 (q, 3C), 25.8 (t), 20.8 (s), 19.2 (s), 19.0 (s), 18.9 (q), 16.6 (q), −3.3 (q), −3.5 (q), −3.8 (q), −3.9 (q). HRMS m/z [M + Na]+ Calcd for C61H88O12SSi3Na 1151.5202. Found 1151.5246.

Cholesteryl 2-O-(3,4-Di-O-Bz-2-O-TBDPS-α-L-rhamnopyranosyl)-3,4-di-O-TBS-6-O-Piv-β-D-glucopyranoside (21)

To a mixture of 10 (35.6 mg, 31.5 µmol) and cholesterol (14.7 mg, 37.8 µmol) in CH2Cl2 (3.0 mL) were added Msv 4A (50.0 mg), 2,6-lutidine (6.75 mg, 63.0 µmol), and MeOTf (20.7 mg, 126 µmol). The mixture was stirred for 6 h at r.t., and then further MeOTf (20.7 mg, 126 µmol) was added. The mixture was stirred for additional 14 h at r.t. Addition of Et3N (2.0 mL) quenched the reaction. The mixture was filtered through a Celite pad. The filtrate was successively washed with H2O and saturated aqueous NaHCO3. After general drying procedure, the mixture was purified by CC (SiO2 5 g, hexane/EtOAc = 1/0, then 50/1 to 10/1) to give 21 (19.1 mg, 42% yield) as a mixture of diastereomer. A part of the mixture was further separated by HPLC (column, Develosil ODS-HG-5; eluent, MeOH/THF = 5/1) to give the α-isomer (4.2 mg) and the β-isomer (6.0 mg), respectively, both as a colorless syrup. The α/β ratio was 44/56 on the basis of the area ratio of the HPLC-chromatogram. Data for 21-α: [α]D22 +15 (c 0.15, CHCl3). IR (ZnSe) 2932, 2858, 1732, 1471, 1275, 1155, 1111, 1066, 1030, 837, 775, 707 cm−1. 1H-NMR (400 MHz, acetone-d6) δ: 7.99–7.97 (m, 2H), 7.82–7.79 (m, 2H), 7.77–7.74 (m, 2H), 7.68–7.66 (m, 2H), 7.62–7.55 (m, 2H), 7.51–7.36 (m, 8H), 7.19 (d, J = 8.0 Hz, 1H), 7.17 (d, J = 7.5 Hz, 1H), 6.00 (dd, J = 10.0, 9.8 Hz, 1H, rha-H4), 5.77 (dd, J = 10.0, 2.5 Hz, 1H, rha-H3), 5.43 (dd, J = 3.6, 1.3 Hz, 1H, agl-H6), 5.17 (d, J = 3.2 Hz, 1H, glc-H1), 4.85 (d, J = 1.8 Hz, 1H, rha-H1), 4.53 (dd, J = 2.5, 1.8 Hz, 1H, rha-H2), 4.49–4.42 (m, 2H, glc-H6, rha-H5), 4.08–3.96 (m, 3H, glc-H3, H5, H6), 3.58 (dd, J = 8.8, 7.1 Hz, 1H, glc-H4), 3.61 (m, 1H, agl-H3), 3.36 (dd, J = 8.2, 3.2 Hz, 1H, glc-H2), 1.39 (d, J = 5.9 Hz, 3H, rha-H6), 1.22 (s, 9H), 1.17 (s, 9H), 1.06 (s, 3H, agl-H19), 0.96 (d, J = 6.6 Hz, 3H, agl-H21), 0.89 (s, 9H), 0.89 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.88 (d, J = 5.4 Hz, 3H, agl-H26 or H27) 0.73 (s, 3H, agl-H18), 0.70 (s, 9H), 0.18 (s, 3H), 0.16 (s, 3H), 0.12 (s, 3H), 0.04 (s, 3H). 13C-NMR (101 MHz, acetone-d6) δ: 178.3 (s), 166.3 (s), 166.0 (s), 141.4 (s), 136.9 (d, 2C), 136.8 (d, 2C), 134.3 (d), 134.2 (s), 134.1 (d), 133.5 (s), 131.1 (d), 130.7 (d), 130.6 (s), 130.6 (s), 130.5 (d, 2C), 130.3 (d, 2C), 129.5 (d, 2C), 129.3 (d, 2C), 128.8 (d, 2C), 128.5 (d, 2C), 122.9 (d), 102.4 (d), 96.6 (d), 81.2 (d), 78.6 (d), 74.2 (d), 73.8 (d), 73.1 (d), 73.0 (d), 72.6 (d), 72.3 (d), 68.2 (d), 64.8 (t), 57.7 (d), 57.0 (d), 51.2 (d), 43.1 (s), 41.4 (t), 40.6 (t), 40.3 (t), 39.4 (s), 38.1 (t), 37.5 (s), 37.0 (t), 36.6 (d), 32.8 (d), 32.7 (t), 29.1 (t), 29.0 (t), 28.7 (d), 27.6 (q, 3C), 27.2 (q, 3C), 26.7 (q, 3C), 26.6 (q, 3C), 25.0 (t), 24.5 (t), 23.1 (q), 22.9 (q), 21.8 (t), 20.1 (s), 19.8 (q), 19.2 (q), 18.8 (s), 18.6 (q), 18.5 (s), 12.3 (q), −1.59 (q), −2.00 (q), −2.77 (q), −3.29 (q). HRMS m/z [M + Na]+ Calcd for C86H128O13Si3Na 1475.8560. Found 1475.8564. Data for 21-β: [α]D23 -20 (c 0.25, CHCl3). IR (ZnSe) 2932, 2858, 1732, 1464, 1275, 1109, 837, 707 cm−1. 1H-NMR (400 MHz, acetone-d6) δ: 7.97–7.93 (m, 2H), 7.78–7.76 (m, 2H), 7.70–7.64 (m, 4H), 7.58–7.51 (m, 2H), 7.38–7.33 (m, 8H), 7.26 (d, J = 7.5 Hz, 1H), 7.24 (d, J = 7.5 Hz, 1H), 5.92 (dd, J = 10.0, 10.0 Hz, 1H, rha-H4), 5.67 (dd, J = 10.0, 2.7 Hz, 1H, rha-H3), 5.41 (dd, J = 3.2, 1.8 Hz, 1H, agl-H6), 5.09 (d, J = 6.6 Hz, 1H, glc-H1), 4.96 (d, J = 1.6 Hz, 1H, rha-H1), 4.62 (dq, J = 10.0, 6.2 Hz, 1H, rha-H5), 4.27 (dd, J = 2.7, 1.6 Hz, 1H, rha-H2), 4.22 (dd, J = 9.1, 7.3 Hz, 1H, glc-H6), 4.18 (dd, J = 9.1, 6.8 Hz, 1H, glc-H6), 4.05 (dd, J = 7.3, 6.8 Hz, 1H, glc-H5), 3.84 (d, J = 3.4 Hz, 1H, glc-H3), 3.69 (d, J = 3.4 Hz, 1H, glc-H4), 3.66 (d, J = 6.6 Hz, 1H, glc-H2), 3.55 (ddd, J = 11.4, 4.6, 4.0 Hz, 1H, agl-H3), 1.35 (d, J = 6.2 Hz, 3H, rha-H6), 1.19 (s, 9H), 1.12 (s, 9H), 0.98 (s, 3H, agl-H19), 0.94 (d, J = 6.4 Hz, 3H, agl-H21), 0.88 (s, 9H), 0.87 (d, J = 6.6 Hz, 3H, agl-H26 or H27) 0.86 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.83 (s, 9H), 0.71 (s, 3H, agl-H18), 0.06 (s, 3H), 0.03 (s, 3H), 0.02 (s, 3H), −0.02 (s, 3H). 13C-NMR (101 MHz, acetone-d6) δ: 178.0 (s), 166.4 (s), 165.9 (s), 141.5 (s), 138.3 (s), 136.7 (d, 2C), 136.7 (d, 2C), 134.2 (d), 134.0 (d), 133.8 (s), 133.6 (s), 131.0 (d), 130.9 (d), 130.7 (s), 130.4 (d, 2C), 130.4 (d, 2C), 129.4 (d, 2C), 129.2 (d, 2C), 128.9 (d, 2C), 128.7 (d, 2C), 126.1 (d), 122.6 (d), 99.2 (d), 97.3 (d), 80.3 (d), 79.9 (d), 78.9 (d), 75.1 (d), 73.0 (d), 72.7 (d), 70.8 (d), 67.7 (d), 65.8 (t), 57.6 (d), 57.1 (d), 51.2 (d), 43.1 (s), 40.7 (t), 40.3 (t), 40.0 (t), 39.3 (s), 38.2 (t), 37.6 (s), 37.0 (t), 36.7 (d), 32.8 (d), 32.7 (t), 31.0 (t), 29.0 (t), 28.7 (d), 27.5 (q, 3C), 27.4 (q, 3C), 26.2 (q, 3C), 26.1 (q, 3C), 25.0 (t), 24.6 (t), 23.1 (q), 22.9 (q), 21.8 (t), 20.1 (s), 19.8 (q), 19.2 (q), 18.6 (s), 18.4 (s), 18.2 (q), 12.3 (q), −4.0 (q), −4.4 (q), −4.4 (q), −4.6 (q). HRMS m/z [M + Na]+ Calcd for C86H128O13Si3Na 1475.8560. Found 1475.8504.

2,4-Di-O-Ac-3-O-Bn-L-rhamnopyranose (26)

To a solution of 2557) (8.00 g, 21.2 mmol) in THF (240 mL) under N2 atmosphere, Ir[(cod)(MePh2P)]PF6 (200 mg, 212 µmol) was added. After the mixture was degassed by diaphragm vacuum pump (10 mmHg), H2 gas was introduced. The mixture was stirred under the H2 atmosphere for 1 min at r.t. During this process, the color of the solution changed from red to yellow. Subsequently, the H2 was replaced with N2 gas, and the mixture was stirred under N2 atmosphere for 20 min. H2O (24 mL) and NIS (6.40 g, 28.4 mmol) was then added to the mixture. The mixture was stirred for additional 40 min at r.t. After addition of aqueous Na2S2O3 (10%, 120 mL), the mixture was extracted with EtOAc. The organic layer was successively washed with H2O and brine. After the general drying procedure, the crude product was purified by CC (SiO2 240 g, hexane/EtOAc = 4/1 to 2/1) to afford 26 (83/17 diastereomeric mixture, 7.20 g, 100%) as a yellow syrup. Data for 26: [α]D25 +25.4 (c 1.15, CHCl3). IR (ZnSe) 3424 cm−1. 1H-NMR of the major isomer (400 MHz, CDCl3) δ: 7.36–7.28 (m, 5H), 5.37 (dd, J = 3.2, 1.8 Hz, 1H, rha-H2), 5.18 (dd, J = 3.9, 1.8 Hz, 1H, rha-H1), 5.03 (dd, J = 9.9, 9.6 Hz, 1H, rha-H4), 4.65 (d, J = 12.4 Hz, 1H), 4.44 (d, J = 12.4 Hz, 1H), 4.00 (dq, J = 9.9, 6.4 Hz, 1H, rha-H5), 3.89 (dd, J = 9.6, 3.2 Hz, 1H, rha-H3), 2.87 (d, J = 3.9 Hz, 1H), 2.15 (s, 3H), 2.02 (s, 3H), 1.19 (d, J = 6.4 Hz, 3H, rha-H6). 13C-NMR of the major isomer (101 MHz, CDCl3) δ: 170.8 (s), 170.3 (s), 138.1 (s), 128.5 (d, 2C), 128.0 (d, 3C), 92.6 (d), 74.2 (d), 72.7 (d), 71.5 (t), 69.1 (d), 66.8 (d), 21.3 (q), 21.2 (q), 17.7 (q). HRMS m/z [M + Na]+ Calcd for C17H22O7Na 361.1260. Found 361.1268.

2,4-Di-O-Ac-3-O-Bn-α-L-rhamnopyranosyl TCAI (24d)

To a stirred solution of 26 (6.00 g, 17.7 mmol) in CH2Cl2 (180 mL) were added Cl3CCN (7.70 g, 53.2 mmol) and DBU (270 mg, 1.77 mmol) at 0 °C. The mixture was stirred for 1 h. CH2Cl2 and excess Cl3CCN was removed by evaporation. The resulting residue was purified by CC (SiO2 200 g, hexane/EtOAc = 10/1 to 6/1) to afford 24d (96/4 diastereomeric mixture, 7.0 g, 82% yield) as a colorless syrup. Data for 24d: [α]D24 −13.3 (c 1.04, CHCl3). IR (ZnSe) 3320, 2986, 2940, 2909, 1752, 1676, 1229, 1051 cm−1. 1H-NMR of the major isomer (400 MHz, CDCl3) δ: 8.69 (s, 1H), 7.35–7.25 (m, 5H), 6.20 (d, J = 1.8 Hz, 1H, rha-H1), 5.48 (dd, J = 3.2, 1.8 Hz, 1H, rha-H2), 5.12 (dd, J = 10.1, 9.9 Hz, 1H, rha-H4), 4.66 (d, J = 12.1 Hz, 1H), 4.46 (d, J = 12.1 Hz, 1H), 3.94 (dq, J = 9.9, 6.2 Hz, 1H, rha-H5), 3.88 (dd, J = 10.1, 3.2 Hz, 1H, rha-H3), 2.19 (s, 3H), 2.05 (s, 3H), 1.23 (d, J = 6.2 Hz, 3H, rha-H6). 13C-NMR of the major isomer (101 MHz, CDCl3) δ: 170.3 (s), 170.1 (s), 160.0 (s), 137.6 (s), 128.6 (d, 2C), 128.3 (d, 2C), 128.2 (d), 95.2 (d), 91.0 (s), 73.9 (d), 71.9 (d), 71.7 (t), 69.7 (d), 67.2 (d), 21.1 (q), 21.1 (q), 17.7 (q). HRMS m/z [M + Na]+ Calcd for C19H22Cl3NO7Na 504.0360. Found 504.0342.

Allyl 2,3-O-Anisilidene-4-O-TBDPS-α-L-rhamnopyranoside (28)

A mixture of allyl α-L-rhamnopyranoside 2758) (28.0 g, 137 mmol), p-methoxybenzaldehyde dimethyl acetal (37.4 g, 206 mmol), and p-TsOH (2.6 g, 14 mmol) in DMF (1.37 L) was stirred for 3 h at 50 °C under 10 mmHg using rotary evaporator. After addition of saturated aqueous NaHCO3 to the reaction mixture, it was extracted with CH2Cl2. The combined organic layer was successively washed with H2O and brine. After the general drying procedure, the mixture was purified by CC (SiO2 500 g, hexane/EtOAc = 5/1 to 2/1) to give 2,3-O-p-methoxybenzylidene acetal product. To a solution of the product in DMF (1.0 L) was added imidazole (4.4 g, 64 mmol), DMAP (3.1 g, 25 mmol), and TBDPSCl (14 g, 51 mmol), and the mixture was stirred for 2 h at 110 °C. After the mixture was cooled to r.t., to this were added further imidazole (4.4 g, 64 mmol), DMAP (3.1 g, 25 mmol), and TBDPSCl (14 g, 51 mmol). The mixture was stirred for 2 h at 110 °C. This protocol was repeated for 3 times, thus total amount of the added imidazole, DMAP, and TBDPSCl were 17.6 g, 12.4 g, and 46 g, respectively. After the mixture was cooled to r.t., H2O (500 mL) was added. The aqueous mixture was extracted with CH2Cl2. The combined organic layer was successively washed with H2O and brine. After general drying procedure, the mixture was successively purified by medium pressure chromatography (SiO2 1 kg, hexane/EtOAc = 30/1 to 10/1) and CC (ODS 250 g, methanol/H2O = 3/1 to 1/0) to give 28 (64/36 mixture of diastereomers, 50.7 g, 66% yield for 2 steps). Partial data for 28: 1H-NMR (400 MHz, CDCl3) δ: 1.04 (s, 9H), 1.07 (s, 9H). HRMS m/z [M + Na]+ Calcd for C33H40O6SiNa 583.2492. Found 583.2500.

Allyl 3-O-PMB-4-O-TBDPS-α-L-rhamnopyranoside (29)

To a solution of 28 (6.00 g, 10.7 mmol) in CH2Cl2 (105 mL) was dropwise added a solution of DIBAL (0.99 mol/L solution in toluene, 31.9 mL, 31.6 mmol) at −20 °C. After the mixture was stirred for 1.5 h at −20 °C, it was poured into 1 M hydrochloric acid (300 mL). The aqueous mixture was extracted with CH2Cl2. The combined organic layer was successively washed with saturated aqueous NaHCO3 and brine. After general drying procedure, the mixture was purified by CC (SiO2 180 g, hexane/EtOAc = 10/1 to 3/1) to give 29 (Rf 0.49 at hexane/EtOAc = 2/1, 4.5 g, 77%) and its isomer 30 (Rf 0.60 at hexane/EtOAc = 2/1, 1.3 g, 22%). Data for 29: [α]D22 −102 (c 1.37, CHCl3). IR (ZnSe) 3555, 3072, 2934, 1614, 1464, 1388, 1304, 1250, 1176, 1093, 995, 821, 706, 609, 501 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.68–7.60 (m, 4H), 7.43–7.00 (m, 6H), 6.71 (d, J = 8.8 Hz, 2H), 6.64 (d, J = 8.8 Hz, 2H), 5.93 (dddd, J = 17.2, 10.0, 6.4, 5.2 Hz, 1H), 5.32 (dd, J = 17.2, 1.6 Hz, 1H), 5.23 (dd, J = 10.0, 1.6 Hz, 1H), 4.79 (d, J = 1.6 Hz, 1H, rha-H1), 4.20 (dd, J = 13.2, 5.2 Hz, 1H), 4.05 (d, J = 10.8 Hz, 1H), 3.99 (ddd, J = 13.2, 6.4 Hz, 1H), 3.94 (br dd, J = 3.2, 1.6 Hz, 1H, rha-H2), 3.84 (dq, J = 9.2, 6.4 Hz, 1H, rha-H5), 3.78 (s, 3H), 3.74 (d, J = 10.8 Hz, 1H), 3.72 (dd, J = 9.2, 3.2 Hz, 1H, rha-H3), 3.60 (dd, J = 9.2, 9.2 Hz, 1H, rha-H4), 2.17 (br s, 1H), 1.29 (d, J = 6.4 Hz, 3H, rha-H6), 0.98 (s, 9H). 13C-NMR (101 MHz, CDCl3) δ: 159.1 (s), 136.2 (s), 135.7 (d), 134.8 (s), 133.9 (d), 132.8 (s), 129.9 (s), 129.4 (d), 129.4 (d), 129.2 (d), 127.3 (d), 127.3 (d), 117.6 (t), 113.5 (d), 98.0 (d), 79.6 (d), 73.7 (d), 69.1 (t), 68.5 (d), 68.0 (t), 67.0 (d), 55.2 (q), 27.1 (q), 19.8 (s), 18.5 (q). HRMS m/z [M + Na]+ Calcd for C33H42O6SiNa 585.2648. Found 585.2647. Data for 30: [α]D22 −50 (c 0.28, CHCl3). IR (ZnSe) 2934, 2858, 1514, 1250, 1111, 821, 704, 511, 482 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.74–7.70 (m, 4H) 7.44–7.36 (m, 6H), 7.00 (d, J = 8.6 Hz, 2H), 6.80 (d, J = 8.6 Hz, 2H), 5.89 (dddd, J = 17.6, 10.4, 6.2, 5.2 Hz, 1H), 5.27 (dd, J = 17.6, 2.0 Hz, 1H), 5.19 (dd, J = 10.4, 2.0 Hz, 1H), 4.70 (d, J = 1.6 Hz, 1H, rha-H1), 4.48 (d, J = 11.6 Hz, 1H), 4.32 (d, J = 11.6 Hz, 1H), 4.16 (dd, J = 12.8, 5.2 Hz, 1H), 3.93 (dd, J = 12.8, 6.2 Hz, 1H), 3.80 (ddd, J = 10.7, 9.2, 3.6 Hz, 1H, rha-H3), 3.79 (s, 3H), 3.74 (dq, J = 9.2, 6.4 Hz, 1H, rha-H5), 3.57 (dd, J = 3.6, 1.6 Hz, 1H, rha-H2), 3.52 (dd, J = 9.2, 9.2 Hz, 1H, rha-H4), 1.55 (br d, J = 10.7 Hz, 1H), 1.26 (d, J = 6.4 Hz, 3H, rha-H6), 1.04 (s, 9H). 13C-NMR (101 MHz, CDCl3) δ: 159.1 (s), 136.1 (d), 135.7 (d), 134.8 (s), 129.9 (d), 129.5 (d), 129.0 (d), 127.7 (s), 127.5 (d), 127.4 (d), 117.2 (d), 113.7 (t), 96.5 (d), 78.2 (d), 76.3 (d), 75.6 (d), 71.6 (d), 68.6 (d), 67.8 (t), 55.2 (q), 27.1 (q), 19.8 (s), 18.3 (q). HRMS m/z [M + Na]+ Calcd for C33H42O6SiNa 585.2648. Found 585.2645.

Allyl 2-O-Bn-3-O-PMB-4-O-TBDPS-α-L-rhamnopyranoside (31)

To a solution of 29 (4.5 g, 8.0 mmol) in DMF (80 mL) were added sodium hydride (NaH) (60% in mineral oil, 0.64 g, 0.38 g as NaH, 16 mmol) and BnBr (2.1 g, 12 mmol) at 0 °C. The mixture was stirred for 40 min at r.t. To the reaction mixture, further NaH (60% in mineral oil, 160 mg, 96 mg as NaH, 4.0 mmol) and BnBr (0.52 g, 3.0 mmol) were added, and it was stirred for additional 1.2 h. Addition of saturated aqueous NH4Cl quenched the reaction. The aqueous mixture was extracted with CH2Cl2. The organic layer was successively washed with H2O and brine. After the general drying procedure, the mixture was purified by CC (SiO2 150 g, hexane/EtOAc = 20/1) to give 31 (5.2 g, 100%) as a colorless oil. Data for 31: [α]D24 −49 (c 0.15, CHCl3). IR (ATR) 3068, 3032, 2931, 2856, 1736, 1613, 1587, 1513, 1455, 1427, 1363, 1327, 1246, 1216, 1174, 1110, 1038, 912, 820, 754, 741, 699 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.66–7.62 (m, 4H), 7.41–7.21 (m, 9H), 7.11–7.09 (m, 2H), 6.68 (d, J = 8.8 Hz, 2H), 6.62 (d, J = 8.8 Hz, 2H), 5.93 (dddd, J = 16.6, 10.4, 6.0, 6.0 Hz, 1H), 5.30 (ddd, J = 16.6, 3.2, 1.6 Hz, 1H), 5.21 (ddd, J = 10.4, 2.8, 1.6 Hz, 1H), 4.79 (d, J = 2.4 Hz, 1H, rha-H1), 4.45 (d, J = 12.0 Hz, 1H), 4.36 (d, J = 12.0 Hz, 1H), 4.20 (ddd, J = 12.8, 6.0, 3.2 Hz, 1H), 4.14 (d, J = 11.2 Hz, 1H), 3.97 (ddt, J = 12.8, 6.0, 2.8 Hz, 1H), 3.95 (dd, J = 8.8, 8.0 Hz, 1H, rha-H4), 3.84–3.69 (m, 3H, rha-H2, H3, H5), 3.75 (s, 3H), 1.25 (d, J = 6.0 Hz, 3H, rha-H6), 0.96 (s, 9H). 13C-NMR (101 MHz, CDCl3) δ: 158.7 (s), 138.6 (s), 136.3 (d, 2C), 135.8 (d, 2C), 134.8 (s), 134.2 (d), 133.6 (s), 130.5 (s), 129.2 (d, 2C), 129.1 (d, 2C), 128.2 (d, 2C), 127.3 (d, 5C), 117.3 (t), 113.2 (d, 4C), 97.5 (d), 79.7 (d), 74.4 (d, 2C), 72.5 (t), 69.8 (d), 69.7 (t), 68.1 (t), 55.3 (q), 27.1 (q, 3C), 19.9 (s), 18.8 (q). HRMS m/z [M + Na]+ Calcd for C40H48O6SiNa 675.3118. Found 675.3127.

Allyl 3,4-Di-O-Ac-2-O-Bn-α-L-rhamnopyranoside (32)

To a stirred mixture of 31 (38.0 g, 58.3 mmol) in CH2Cl2 (500 mL) and H2O (25 mL) at r.t., DDQ (117 mg, 510 µmol) was added. The mixture was stirred for 10 min at r.t. The reaction was quenched with saturated aqueous NaHCO3 (100 mL). The mixture was successively washed with H2O and brine. The general drying procedure gave a crude product, of which the main content was mono-ol. To a solution of the crude product in THF (300 mL), a 1.0 M solution of TBAF (117 mL) was added. The mixture was stirred for 20 min at r.t. THF was removed by evaporation to give a crude product, of which the main content was diol. To the crude product were added pyridine (500 mL), Ac2O (16.5 mL), and DMAP (2.80 g, 23.3 mmol). The mixture was stirred for 1 h at r.t. Pyridine and excess Ac2O were azeotropically removed by evaporation with toluene. The resulting residue was purified by CC (SiO2 500 g, hexane/EtOAc = 5/1 to 1/5) to afford 32 (18.8 g, 70% yield for 3 steps) as a yellow syrup. Data for 32: [α]D24 −39.5 (c 1.31, CHCl3). IR (ZnSe) 2984, 2936, 2874, 1744, 1248, 1042 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.36–7.27 (m, 5H), 5.86 (dddd, J = 17.4, 10.6, 6.2, 5.0 Hz, 1H), 5.26 (ddd, J = 17.4, 3.2, 1.6 Hz, 1H), 5.21–5.19 (m, 2H, rha-H3, H4), 5.19 (ddd, J = 10.6, 3.2, 1.6 Hz, 1H), 4.81 (d, J = 1.6 Hz, 1H, rha-H1), 4.66 (d, J = 12.4 Hz, 1H), 4.62 (d, J = 12.4 Hz, 1H), 4.15 (ddd, J = 13.0, 5.0, 3.2 Hz, 1H), 3.96 (ddd, J = 13.0, 6.2, 3.2 Hz, 1H), 3.83 (dq, J = 8.9, 6.2 Hz, 1H, rha-H5), 3.83 (dd, J = 2.7, 1.6 Hz, 1H, rha-H2), 2.04 (s, 3H), 1.99 (s, 3H), 1.22 (d, J = 6.2 Hz, 3H, rha-H6). 13C-NMR (101 MHz, CDCl3) δ: 170.3 (s), 170.0 (s), 137.9 (s), 133.6 (d), 128.5 (d, 2C), 128.0 (d, 2C), 127.9 (d), 117.6 (t), 97.0 (d), 75.8 (d), 73.3 (t), 71.7 (d), 71.5 (d), 68.1 (t), 66.0 (d), 21.0 (q), 20.9 (q), 17.6 (q). HRMS m/z [M + Na]+ Calcd for C20H26O7Na 401.1576. Found 401.1579.

3,4-Di-O-Ac-2-O-Bn-L-rhamnopyranose (33)

To a solution of 32 (12.0 g, 31.7 mmol) in THF (320 mL) was added [Ir(cod)(MePh2P)2]PF6 (270 mg, 317 µmol) under N2 atmosphere. After the mixture was degassed by diaphragm vacuum pump (10 mmHg), H2 gas was introduced. The mixture was stirred under the H2 atmosphere for 1 min at r.t. During this process, the color of the solution changed from red to yellow. Subsequently, the H2 was replaced with N2 gas, and the mixture was stirred under N2 atmosphere for 10 min. To the mixture was added H2O (32 mL) and NIS (7.90 g, 34.9 mmol). The mixture was stirred for 10 min at r.t. The reaction was quenched with aqueous Na2S2O3 (10%, 160 mL). The mixture was extracted with EtOAc. The combined organic layer was successively washed with H2O and brine. After the general drying procedure, the mixture was purified by CC (SiO2 300 g, hexane/EtOAc = 5/1 to 1/1) to afford 33 (90/10 mixture of diastereomers, 11 g, 100%) as a yellow syrup. Data for 33: IR (ZnSe) 3449, 3422 cm−1. 1H-NMR of the major isomer (400 MHz, CDCl3) δ: 7.37–7.27 (m, 5H), 5.27 (dd, J = 10.0, 3.0 Hz, 1H, rha-H3), 5.21 (dd, J = 10.0, 9.2 Hz, 1H, rha-H4), 5.19 (dd, J = 3.4, 2.1 Hz, 1H, rha-H1), 4.65 (s, 2H), 4.06 (dq, J = 9.2, 6.2 Hz, 1H, rha-H5), 3.86 (dd, J = 3.0, 2.1 Hz, 1H, rha-H2), 2.90 (d, J = 3.4 Hz, 1H), 2.05 (s, 3H), 2.00 (s, 3H), 1.22 (d, J = 6.2 Hz, 3H, rha-H6). 13C-NMR of the major isomer (101 MHz, CDCl3) δ: 170.6 (s), 170.2 (s), 137.9 (s), 128.6 (d, 2C), 128.2 (d, 2C), 128.1 (d), 92.9 (d), 76.0 (d), 73.5 (t), 71.8 (d), 71.3 (d), 66.8 (d), 21.1 (q), 21.1 (q), 17.8 (q). HRMS m/z [M + Na]+ Calcd for C17H22O7Na 361.1263. Found 361.1249.

3,4-Di-O-Ac-2-O-Bn-α-L-rhamnopyranosyl TCAI (24e)

To a solution of 33 (7.60 g, 22.4 mmol) in CH2Cl2 (200 mL) were added Cl3CCN (9.70 g, 22.4 mmol) and DBU (340 mg, 2.24 mmol) at 0 °C. The mixture was stirred for 2 h at 0 °C. CH2Cl2 and excess Cl3CCN were removed by evaporation. The resulting residue was purified by CC (SiO2 300 g, hexane/EtOAc = 8/1 to 5/1) to afford 24e (97/3 mixture of diastereomers, 10.2 g, 94% yield) as a yellow syrup. Data for 24e: [α]D25 −14 (c 0.93, CHCl3). IR (ZnSe) 3330, 3033, 2986, 2940, 2913, 1748, 1674, 1240, 1055 cm−1. 1H-NMR of the major isomer (400 MHz, CDCl3) δ: 8.62 (s, 1H), 7.39–7.28 (m, 5H), 6.28 (d, J = 2.1 Hz, 1H, rha-H1), 5.29 (dd, J = 10.1, 9.6 Hz, 1H, rha-H4), 5.22 (dd, J = 10.1, 3.2 Hz, 1H, rha-H3), 4.75 (d, J = 12.4 Hz, 1H), 4.63 (d, J = 12.4 Hz, 1H), 4.06 (dd, J = 3.2, 2.1 Hz, 1H, rha-H2), 4.05 (dq, J = 9.6, 6.2 Hz, 1H, rha-H5), 2.06 (s, 3H), 1.97 (s, 3H), 1.27 (d, J = 6.2 Hz, 3H, rha-H6). 13C-NMR of the major isomer (101 MHz, CDCl3) δ: 170.4 (s), 170.0 (s), 160.6 (s), 137.6 (s), 128.6 (d, 2C), 128.2 (d, 3C), 95.7 (d), 91.1 (s), 74.1 (d), 73.4 (t), 71.0 (d), 70.9 (d), 69.7 (d), 21.0 (q, 2C), 17.8 (q). HRMS m/z [M + Na]+ Calcd for C19H22Cl3NO7Na 504.0360. Found 504.0347.

Ethyl 3,4,6-Tri-O-Ac-2-O-(3-O-Ac-2,4-di-O-Bn-α-L-rhamnopyranosyl)-1-thio-β-D-glucopyranoside (34a)

To a solution of a mixture of 2353) (2.20 g, 6.30 mmol) and 24a54) (5.00 g, 9.45 mmol) in CH2Cl2 (100 mL) were added Msv 4A (2.2 g) and TMSOTf (1.10 g, 4.73 mmol). The mixture was stirred for 20 min at 0 °C. The reaction was quenched with saturated aqueous NaHCO3 (50 mL). The aqueous mixture was filtered through a Celite pad. After separation of the organic layer, it was successively washed with H2O and brine. After the general drying procedure, the mixture was purified by CC (SiO2 90 g, CH2Cl2/EtOAc = 100/1 to 10/1) to afford 34a (3.3 g, 73% yield) as a white powder. Data for 34a: mp 108–109 °C. [α]D24 −10.5 (c 1.15, CHCl3). IR (ZnSe) 2975, 2934, 1750, 1364, 1237, 1100, 1042 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.36–7.26 (m, 10H), 5.24 (dd, J = 9.2, 8.9 Hz, 1H, glc-H3), 5.18 (dd, J = 7.8, 3.0 Hz, 1H, rha-H3), 4.99 (d, J = 2.8 Hz, 1H, rha-H1), 4.97 (dd, J = 9.8, 8.9 Hz, 1H, glc-H4), 4.69 (d, J = 11.2 Hz, 1H), 4.60 (d, J = 11.2 Hz, 1H), 4.57 (d, J = 11.9 Hz, 1H), 4.49 (d, J = 11.9 Hz, 1H), 4.48 (d, J = 9.6 Hz, 1H, glc-H1), 4.23 (dd, J = 12.4, 5.3 Hz, 1H, glc-H6), 4.19 (dq, J = 9.2, 5.7 Hz, 1H, rha-H5), 4.11 (dd, J = 12.4, 2.3 Hz, 1H, glc-H6), 3.79 (dd, J = 9.6, 9.2 Hz, 1H, glc-H2), 3.74 (dd, J = 3.0, 2.8 Hz, 1H, rha-H2), 3.69 (ddd, J = 9.8, 5.3, 2.3 Hz, 1H, glc-H5), 3.53 (dd, J = 9.2, 7.8 Hz, 1H, rha-H4), 2.80–2.66 (m, 2H) 2.06 (s, 3H), 2.00 (s, 3H), 1.96 (s, 3H), 1.90 (s, 3H), 1.30 (t, J = 7.6 Hz, 3H), 1.29 (d, J = 5.7 Hz, 3H, rha-H6). 13C-NMR (101 MHz, CDCl3) δ: 170.8 (s), 170.3 (s), 170.0 (s), 169.9 (s), 138.3 (s), 137.9 (s), 128.6 (d, 2C), 128.6 (d, 2C), 128.0 (d), 128.0 (d, 4C), 127.9 (d), 99.4 (d), 84.4 (d), 79.8 (d), 77.1 (d), 77.0 (d), 75.7 (d), 75.5 (d), 74.3 (t), 73.2 (t), 72.4 (d), 69.0 (d), 68.9 (d), 62.6 (t), 24.8 (t), 21.2 (q), 20.9 (q, 2C), 20.8 (q), 18.2 (q), 15.0 (q). HRMS m/z [M + Na]+ Calcd for C36H46O13SNa 741.2557. Found 741.2547.

Ethyl 3,4,6-Tri-O-Ac-2-O-(4-O-Ac-2,3-di-O-Bn-α-L-rhamnopyranosyl)-1-thio-β-D-glucopyranoside (34b)

In a reaction similar to that described for the synthesis of 34a, the use of 23 (2.80 g, 7.94 mmol), 24b55) (6.30 g, 11.9 mmol), Msv 4A (6.3 g), and TMSOTf (1.30 g, 5.95 mmol) provided a crude product containing 34b. The crude product was purified by recrystallization from a mixture of hexane and EtOAc to afford 34b (2.6 g) as a white powder. The mother liquid was further purified with CC (SiO2 60 g, CH2Cl2/EtOAc = 50/1 to 10/1) to give additional 34b (0.5 g; total 3.1 g, 55% yield). Data for 34b: mp 158–160 °C. [α]D24 −19.5 (c 1.01, CHCl3). IR (ZnSe) 2943, 2940, 1750, 1237, 1102, 1042 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.35–7.24 (m, 10H), 5.21 (dd, J = 9.8, 8.9 Hz, 1H, glc-H3), 5.18 (dd, J = 9.4, 9.2 Hz, 1H, rha-H4), 5.01 (d, J = 2.3 Hz, 1H, rha-H1), 4.97 (dd, J = 9.8, 9.8 Hz, 1H, glc-H4), 4.70 (d, J = 12.2 Hz, 1H), 4.59 (d, J = 12.4 Hz, 1H), 4.58 (d, J = 12.2 Hz, 1H), 4.51 (d, J = 12.4 Hz, 1H), 4.43 (d, J = 9.6 Hz, 1H, glc-H1), 4.23 (dd, J = 12.4, 5.0 Hz, 1H, glc-H6), 4.19 (dq, J = 9.4, 6.2 Hz, 1H, rha-H5), 4.12 (dd, J = 12.4, 2.3 Hz, 1H, glc-H6), 3.78 (dd, J = 9.6, 8.9 Hz, 1H, glc-H2), 3.70 (dd, J = 9.2, 3.0 Hz, 1H, rha-H3), 3.68 (ddd, J = 9.8, 5.0, 2.3 Hz, 1H, glc-H5), 3.67 (dd, J = 3.0, 2.3 Hz, 1H, rha-H2), 2.81–2.66 (m, 2H), 2.07 (s, 3H), 2.02 (s, 3H), 2.01 (s, 3H), 1.88 (s, 3H), 1.29 (t, J = 7.4 Hz, 3H), 1.18 (d, J = 6.2 Hz, 3H, rha-H6). 13C-NMR (101 MHz, CDCl3) δ: 170.8 (s), 170.3 (s, 2C), 169.8 (s), 138.5 (s), 138.3 (s), 128.5 (d, 2C), 128.5 (d, 2C), 127.8 (d, 3C), 127.7 (d), 127.5 (d, 2C), 100.1 (d), 84.1 (d), 77.4 (d), 76.9 (d), 76.1 (d), 75.7 (d), 75.6 (d), 73.3 (t), 73.2 (d), 72.1 (t), 68.8 (d), 68.3 (d), 62.4 (t), 24.2 (t), 21.3 (q), 20.9 (q), 20.8 (q), 20.8 (q), 17.7 (q), 14.9 (q). HRMS m/z [M + Na]+ Calcd for C36H46O13SNa 741.2557. Found 741.2552.

Ethyl 3,4,6-Tri-O-Ac-2-O-(2,3-di-O-Ac-4-O-Bn-α-L-rhamnopyranosyl)-1-thio-β-D-glucopyranoside (34c)

In a reaction similar to that described for the synthesis of 34a, the use of 23 (2.10 g, 5.96 mmol), 24c56) (4.30 g, 8.94 mmol), CH2Cl2 (150 mL), Msv 4A (6.4 g), and TMSOTf (1.00 g, 4.47 mmol) provided a crude product containing 34c. The crude product was purified by recrystallization from a mixture of hexane and EtOAc to afford 34c (2.00 g, 50% yield) as a white powder. Data for 34c: mp 168–170 °C. [α]D24 −11.7 (c 1.03, CHCl3). IR (ZnSe) 2977, 2934, 1750, 1374, 1244, 1225, 1044 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.36–7.28 (m, 5H), 5.28 (dd, J = 9.2, 3.2 Hz, 1H, rha-H3), 5.24 (dd, J = 9.6, 9.2 Hz, 1H, glc-H3), 5.00 (dd, J = 3.2, 2.0 Hz, 1H, rha-H2), 4.95 (dd, J = 9.8, 9.6 Hz, 1H, glc-H4), 4.91 (d, J = 2.0 Hz, 1H, rha-H1), 4.67 (d, J = 11.4 Hz, 1H), 4.62 (d, J = 11.4 Hz, 1H), 4.49 (d, J = 9.6 Hz, 1H, glc-H1), 4.33 (dq, J = 9.6, 6.2 Hz, 1H, rha-H5), 4.23 (dd, J = 12.4, 5.3 Hz, 1H, glc-H6), 4.10 (dd, J = 12.4, 2.3 Hz, 1H, glc-H6), 3.72 (dd, J = 9.6, 9.2 Hz, 1H, glc-H2), 3.69 (ddd, J = 9.8, 5.3, 2.3 Hz, 1H, glc-H5), 3.50 (dd, J = 9.6, 9.2 Hz, 1H, rha-H4), 2.81–2.66 (m, 2H), 2.11 (s, 3H), 2.06 (s, 3H), 2.05 (s, 3H), 2.01 (s, 3H), 1.97 (s, 3H), 1.30 (d, J = 6.2 Hz, 3H, rha-H6), 1.30 (t, J = 7.6 Hz, 3H). 13C-NMR (101 MHz, CDCl3) δ: 170.8 (s), 170.3 (s), 170.0 (s), 170.0 (s), 169.9 (s), 138.2 (s), 128.6 (d, 2C), 128.0 (d), 127.9 (d, 2C), 98.9 (d), 84.3 (d), 79.1 (d), 77.3 (d), 76.5 (d), 75.7 (d), 74.9 (t), 71.2 (d), 70.9 (d), 69.0 (d), 69.0 (d), 62.6 (t), 24.7 (t), 21.1 (q), 21.1 (q), 20.9 (q, 2C), 20.8 (q), 17.8 (q), 15.0 (q). HRMS m/z [M + Na]+ Calcd for C31H42O14SNa 693.2193. Found 693.2206.

Ethyl 3,4,6-Tri-O-Ac-2-O-(2,4-di-O-Ac-3-O-Bn-α-L-rhamnopyranosyl)-1-thio-β-D-glucopyranoside (34d)

In a reaction similar to that described for the synthesis of 34a, the use of 23 (3.10 g, 9.01 mmol), 24d (6.50 g, 13.5 mmol), CH2Cl2 (200 mL), Msv 4A (9.6 g), and TMSOTf (1.50 g, 6.76 mmol) provided a crude product containing 34d. The crude product was purified by recrystallization from a mixture of hexane and EtOAc to afford 34d (3.7 g, 62% yield) as a white powder. Data for 34d: mp 194–197 °C. [α]D24 +9.50 (c 1.01, CHCl3). IR (ZnSe) 2934, 1750, 1237, 1100, 1075, 1042 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.35–7.26 (m, 5H), 5.23 (dd, J = 9.6, 9.4 Hz, 1H, glc-H3), 5.09 (dd, J = 3.0, 2.0 Hz, 1H, rha-H2), 5.04 (dd, J = 9.9, 9.6 Hz, 1H, rha-H4), 4.98 (dd, J = 9.8, 9.6 Hz, 1H, glc-H4), 4.93 (d, J = 2.0 Hz, 1H, rha-H1), 4.60 (d, J = 12.4 Hz, 1H), 4.45 (d, J = 9.6 Hz, 1H, glc-H1), 4.41 (d, J = 12.4 Hz, 1H), 4.24 (dq, J = 9.9, 6.2 Hz, 1H, rha-H5), 4.23 (dd, J = 12.4, 5.0 Hz, 1H, glc-H6), 4.12 (dd, J = 12.4, 2.3 Hz, 1H, glc-H6), 3.73 (dd, J = 9.6, 3.0 Hz, 1H, rha-H3), 3.71 (dd, J = 9.6, 9.4 Hz, 1H, glc-H2), 3.68 (ddd, J = 9.8, 5.0, 2.3 Hz, 1H, glc-H5), 2.81–2.66 (m, 2H), 2.11 (s, 3H), 2.10 (s, 3H), 2.07 (s, 3H), 2.03 (s, 3H), 2.03 (s, 3H), 1.29 (t, J = 7.6 Hz, 3H), 1.17 (d, J = 6.2 Hz, 3H, rha-H6). 13C-NMR (101 MHz, CDCl3) δ: 170.8 (s), 170.7 (s), 170.4 (s), 170.2 (s), 169.8 (s), 138.1 (s), 128.5 (d, 2C), 127.8 (d), 127.8 (d, 2C), 99.6 (d), 84.0 (d), 78.0 (d), 76.4 (d), 75.8 (d), 74.4 (d), 72.5 (d), 71.4 (t), 69.0 (d), 68.8 (d), 67.8 (d), 62.4 (t), 24.2 (t), 21.1 (q), 21.1 (q), 21.0 (q), 20.9 (q), 20.8 (q), 17.3 (q), 14.9 (q). HRMS m/z [M + Na]+ Calcd for C31H42O14SNa 693.2193. Found 693.2177.

Ethyl 3,4,6-Tri-O-Ac-2-O-(3,4-di-O-Ac-2-O-Bn-α-L-rhamnopyranosyl)-1-thio-β-D-glucopyranoside (34e)

In a reaction similar to that described for the synthesis of 34a, the use of 23 (3.20 g, 9.22 mmol), 24e (8.90 g, 18.4 mmol), CH2Cl2 (250 mL), Msv 4A (5 g), and TMSOTf (1.50 g, 6.94 mmol) provided a crude product containing 34e. The crude product was purified by CC (SiO2 100 g, CH2Cl2/EtOAc = 50/1 to 10/1) to afford 34e (5.5 g, 90% yield) as a white solid. Data for 34e: mp 55–57 °C. [α]D24 −22.1 (c 1.12, CHCl3). IR (ZnSe) 3033, 2982, 2938, 2874, 1748, 1368, 1240, 1040, 914 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.36–7.27 (m, 5H), 5.24 (dd, J = 9.6, 9.0 Hz, 1H, glc-H3), 5.16 (m, 2H, rha-H3, H4), 5.02 (d, J = 1.8 Hz, 1H, rha-H1), 4.98 (dd, J = 9.8, 9.6 Hz, 1H, glc-H4), 4.57 (s, 2H), 4.49 (d, J = 9.8 Hz, 1H, glc-H1), 4.33 (dq, J = 9.8, 6.2 Hz, 1H, rha-H5), 4.24 (dd, J = 12.4, 5.0 Hz, 1H, glc-H6), 4.12 (dd, J = 12.4, 2.3 Hz, 1H, glc-H6), 3.80 (dd, J = 9.8, 9.0 Hz, 1H, glc-H2), 3.71 (dd, J = 2.3, 1.8 Hz, 1H, rha-H2), 3.69 (ddd, J = 9.8, 5.0, 2.3 Hz, 1H, glc-H5), 2.83–2.68 (m, 2H), 2.07 (s, 3H), 2.04 (s, 3H), 2.01 (s, 3H), 1.97 (s, 3H), 1.92 (s, 3H), 1.32 (t, J = 7.6 Hz, 3H), 1.20 (d, J = 6.2 Hz, 3H, rha-H6). 13C-NMR (101 MHz, CDCl3) δ: 170.8 (s), 170.3 (s), 170.1 (s), 170.0 (s), 169.8 (s), 137.8 (s), 128.6 (d, 2C), 128.0 (d), 127.8 (d, 2C), 99.2 (d), 84.1 (d), 77.1 (d), 76.8 (d), 75.9 (d), 75.7 (d), 73.5 (t), 71.8 (d), 71.1 (d), 68.8 (d), 67.9 (d), 62.5 (t), 24.6 (t), 21.0 (q, 2C), 20.9 (q, 2C), 20.8 (q), 17.5 (q), 15.0 (q). HRMS m/z [M + Na]+ Calcd for C31H42O14SNa 693.2193. Found 693.2211.

Ethyl 2-O-(2,4-Di-O-Bn-3-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-1-thio-β-D-glucopyranoside (22a)

To a suspension of 34a (3.30 g, 4.59 mmol) in MeOH (46 mL) was added NaOMe (240 mg, 4.60 mmol). The mixture was stirred for 2 h at reflux. After the mixture was cooled to r.t., it was neutralized by addition of Amberlite IR 120B (H+). The mixture was filtered through a cotton-pad to remove the Amberlite. The filtrate was concentrated. To a solution of the resulting residue in DMF (46 mL) were added 2,6-lutidine (7.90 g, 73.5 mmol) and TBSOTf (14.6 g, 55.1 mmol). The mixture was stirred for 1.5 h at 100 °C. The reaction was quenched with H2O (50 mL). The mixture was extracted with hexane. The organic layer was successively washed with 1 M hydrochloric acid, saturated aqueous NaHCO3, and brine. After the general drying procedure, the crude product was purified by CC (SiO2 130 g, hexane/EtOAc = 1/0 to 20/1) to afford 22a (4.3 g, 94% yield, for 2 steps) as a white solid. Data for 22a: mp 75–78 °C. [α]D25 −60.1 (c 1.38, CHCl3). IR (ZnSe) 2955, 2930, 2886, 2859, 1472, 1254, 1102, 837, 776 cm−1. 1H-NMR (400 MHz, acetone-d6) δ: 7.43–7.25 (m, 10H), 5.08 (d, J = 1.4 Hz, 1H, rha-H1), 4.91 (d, J = 11.7 Hz, 1H), 4.88 (d, J = 12.0 Hz, 1H), 4.85 (d, J = 8.9 Hz, 1H, glc-H1), 4.70 (d, J = 12.0 Hz, 1H), 4.66 (d, J = 11.7 Hz, 1H), 4.16 (dd, J = 9.4, 3.0 Hz, 1H, rha-H3), 4.07 (dq, J = 9.4, 6.2 Hz, 1H, rha-H5), 4.03 (br d, J = 3.2 Hz, 1H, glc-H3), 3.97 (d, J = 3.2 Hz, 1H, glc-H4), 3.83 (dd, J = 6.9, 6.9 Hz, 1H, glc-H5), 3.82–3.76 (m, 3H, glc-H2, H6, H6), 3.68 (dd, J = 3.0, 1.4 Hz, 1H, rha-H2), 3.53 (dd, J = 9.4, 9.4 Hz, 1H, rha-H4), 2.80–2.57 (m, 2H), 1.29 (t, J = 7.3 Hz, 3H), 1.21 (d, J = 6.2 Hz, 3H, rha-H6), 0.97 (s, 9H), 0.93 (s, 9H), 0.93 (s, 9H), 0.92 (s, 9H), 0.18 (s, 3H), 0.16 (s, 3H), 0.15 (s, 3H), 0.13 (s, 3H), 0.11 (s, 6H), 0.10 (s, 6H). 13C-NMR (101 MHz, acetone-d6) δ: 139.9 (s, 2C), 129.1 (d, 2C), 129.0 (d, 2C), 128.3 (d), 128.3 (d, 2C), 128.2 (d, 2C), 128.1 (d), 95.0 (d), 84.6 (d), 81.9 (d), 81.2 (d), 81.1 (d), 77.3 (d), 75.5 (t), 74.4 (t), 74.1 (d), 73.5 (d), 70.9 (d), 69.7 (d), 65.0 (t), 26.5 (q, 3C), 26.4 (q, 3C), 26.3 (q, 3C), 26.2 (q, 3C), 24.8 (t), 18.9 (s), 18.7 (s), 18.6 (s), 18.4 (s), 18.3 (q), 15.8 (q), −3.9 (q), −4.2 (q), −4.2 (q), −4.3 (q), −4.4 (q), −4.6 (q), −5.0 (q, 2C). HRMS m/z [M + Na]+ Calcd for C52H94O9SSi4 1029.5593. Found 1029.5547.

Ethyl 2-O-(2,3-Di-O-Bn-4-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-1-thio-β-D-glucopyranoside (22b)

In a reaction similar to that described for the synthesis of 22a, the use of 34b (1.90 g, 2.65 mmol), MeOH (26 mL), NaOMe (290 mg, 5.29 mmol), DMF (26 mL), 2,6-lutidine (4.50 g, 42.3 mmol), and TBSOTf (8.40 g, 55.1 mmol) provided a crude product containing 22b. The crude product was purified by CC (SiO2 60 g, hexane/EtOAc = 100/1 to 30/1) to afford 22b (2.9 g, 100%, for 2 steps) as a colorless syrup. Data for 22b: [α]D25 −58.0 (c 1.23, CHCl3). IR (ZnSe) 2955, 2930, 2886, 2857, 1472, 1254, 1103, 837, 777 cm−1. 1H-NMR (400 MHz, acetone-d6) δ: 7.43–7.27 (m, 10H), 5.09 (d, J = 1.6 Hz, 1H, rha-H1), 4.81 (d, J = 8.5 Hz, 1H, glc-H1), 4.74 (d, J = 12.1 Hz, 1H), 4.69 (d, J = 12.1 Hz, 1H), 4.66 (d, J = 11.9 Hz, 1H), 4.51 (d, J = 11.9 Hz, 1H), 4.14 (dq, J = 9.4, 6.4 Hz, 1H, rha-H5), 4.02 (br d, J = 3.2 Hz, 1H, glc-H3), 3.94 (d, J = 3.2 Hz, 1H, glc-H4), 3.94 (dd, J = 3.0, 1.6 Hz, 1H, rha-H2), 3.84–3.76 (m, 4H, glc-H2, H5, H6, H6), 3.79 (dd, J = 9.4, 9.4 Hz, 1H, rha-H4), 3.64 (dd, J = 9.4, 3.0 Hz, 1H, rha-H3), 2.77–2.60 (m, 2H), 1.28 (t, J = 7.3 Hz, 3H), 1.25 (d, J = 6.4 Hz, 3H, rha-H6), 0.94 (s, 9H), 0.93 (s, 9H), 0.91 (s, 9H), 0.88 (s, 9H), 0.19 (s, 3H), 0.17 (s, 3H), 0.13 (s, 3H), 0.11 (s, 3H), 0.11 (s, 3H), 0.10 (s, 3H), 0.10 (s, 3H), 0.02 (s, 3H). 13C-NMR (101 MHz, acetone-d6) δ: 139.7 (s), 139.5 (s), 129.2 (d, 2C), 129.0 (d, 2C), 128.4 (d), 128.4 (d, 2C), 128.2 (d, 2C), 128.1 (d), 96.0 (d), 84.6 (d), 81.5 (d), 81.0 (d), 78.6 (d), 75.8 (d), 74.5 (d), 74.1 (d), 73.5 (t), 71.9 (t), 70.7 (d), 70.6 (d), 65.2 (t), 26.4 (q, 3C), 26.4 (q, 3C), 26.3 (q, 3C), 26.3 (q, 3C), 24.8 (t), 19.0 (s), 18.8 (s), 18.8 (q), 18.6 (s), 18.5 (s), 15.6 (q), −3.3 (q), −4.1 (q), −4.2 (q), −4.2 (q), −4.3 (q), −4.5 (q), −5.0 (q), −5.0 (q). HRMS m/z [M + Na]+ Calcd for C52H94O9SSi4Na 1029.5593. Found 1029.5641.

Ethyl 2-O-(4-O-Bn-2,3-di-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-1-thio-β-D-glucopyranoside (22c)

In a reaction similar to that described for the synthesis of 22a, the use of 34c (1.50 g, 2.24 mmol), MeOH (25 mL), NaOMe (120 mg, 2.24 mmol), DMF (25 mL), 2,6-lutidine (4.80 g, 44.8 mmol), and TBSOTf (8.90 g, 33.6 mmol) provided a crude product containing 22c. The crude product was purified by CC (SiO2 90 g, hexane/EtOAc = 1/0 to 20/1) to afford 22c (2.1 g, 93% yield, for 2 steps) as a white solid. Data for 22c: mp 108–110 °C. [α]D25 −51.3 (c 1.04, CHCl3). IR (ZnSe) 2955, 2930, 2886, 2859, 1474, 1254, 1102, 835, 776 cm−1. 1H-NMR (400 MHz, acetone-d6) δ: 7.39–7.25 (m, 5H), 4.89 (d, J = 1.8 Hz, 1H, rha-H1), 4.86 (d, J = 11.7 Hz, 1H), 4.85 (d, J = 8.9 Hz, 1H, glc-H1), 4.62 (d, J = 11.7 Hz, 1H), 4.11 (dd, J = 9.4, 2.5 Hz, 1H, rha-H3), 4.06 (br d, J = 3.2 Hz, 1H, glc-H3), 4.02 (dq, J = 9.4, 6.2 Hz, 1H, rha-H5), 3.97 (d, J = 3.2 Hz, 1H, glc-H4), 3.87 (dd, J = 2.5, 1.8 Hz, 1H, rha-H2), 3.84 (d, J = 6.9 Hz, 1H, glc-H5), 3.77 (m, 3H, glc-H2, H6, H6), 3.51 (dd, J = 9.4, 9.4 Hz, 1H, rha-H4), 2.79–2.57 (m, 2H), 1.30 (t, J = 7.3 Hz, 3H), 1.14 (d, J = 6.2 Hz, 3H, rha-H6), 0.97 (s, 9H), 0.96 (s, 9H), 0.96 (s, 9H), 0.93 (s, 9H), 0.93 (s, 9H), 0.20 (s, 3H), 0.18 (s, 3H), 0.16 (s, 6H), 0.15 (s, 3H), 0.14 (s, 3H), 0.12 (s, 3H), 0.11 (s, 6H), 0.11 (s, 3H). 13C-NMR (101 MHz, acetone-d6) δ: 139.9 (s), 129.0 (d, 2C), 128.6 (d, 2C), 128.1 (d), 96.3 (d), 84.9 (d), 81.2 (d), 81.1 (d), 76.6 (d), 75.5 (t), 75.0 (d), 73.8 (d), 73.0 (d), 70.9 (d), 70.3 (d), 65.1 (t), 26.8 (q, 3C), 26.4 (q, 6C), 26.2 (q, 6C), 24.9 (t), 18.9 (s), 18.8 (s), 18.8 (s), 18.6 (s), 18.5 (s), 18.5 (q), 15.8 (q), −3.7 (q), −3.9 (q), −4.1 (q), −4.1 (q), −4.2 (q), −4.2 (q), −4.3 (q), −4.6 (q), −5.0 (q), −5.0 (q). HRMS m/z [M + Na]+ Calcd for C51H102O9SSi5Na 1053.5989. Found 1053.5943.

Ethyl 2-O-(3-O-Bn-2,4-di-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-1-thio-β-D-glucopyranoside (22d)

In a reaction similar to that described for the synthesis of 22a, the use of 34d (2.60 g, 3.88 mmol), MeOH (40 mL), NaOMe (110 mg, 1.94 mmol), DMF (40 mL), 2,6-lutidine (8.30 g, 77.6 mmol), and TBSOTf (15.4 g, 58.1 mmol) provided a crude product containing 22d. The crude product was purified by CC (SiO2 60 g, hexane/EtOAc = 1/0 to 20/1) to afford 22d (4.0 g, 99% yield, for 2 steps) as a pale yellow solid. Data for 22d: mp 53–55 °C. [α]D25 −30.6 (c 1.71, CHCl3). IR (ZnSe) 2955, 2930, 2859, 1474, 1254, 1103, 837, 776 cm−1. 1H-NMR (400 MHz, acetone-d6) δ: 7.42–7.25 (m, 5H), 4.89 (d, J = 1.8 Hz, 1H, rha-H1), 4.79 (d, J = 8.7 Hz, 1H, glc-H1), 4.69 (d, J = 11.9 Hz, 1H), 4.51 (d, J = 11.9 Hz, 1H), 4.15 (dq, J = 9.2, 6.2 Hz, 1H, rha-H5), 4.15 (dd, J = 2.5, 1.8 Hz, 1H, rha-H2), 4.05 (br d, J = 3.4 Hz, 1H, glc-H3), 3.96 (d, J = 3.4 Hz, 1H, glc-H4), 3.86–3.76 (m, 4H, glc-H2, H5, H6, H6), 3.79 (dd, J = 9.2, 9.2 Hz, 1H, rha-H4), 3.57 (dd, J = 9.2, 2.5 Hz, 1H, rha-H3), 2.78–2.59 (m, 2H), 1.28 (t, J = 7.3 Hz, 3H), 1.23 (d, J = 6.2 Hz, 3H, rha-H6), 0.97 (s, 9H), 0.94 (s, 18H), 0.93 (s, 9H), 0.87 (s, 9H), 0.19 (s, 3H), 0.17 (s, 3H), 0.17 (s, 3H), 0.16 (s, 3H), 0.11 (s, 3H), 0.11 (s, 3H), 0.10 (s, 3H), 0.09 (s, 6H), 0.01 (s, 3H). 13C-NMR (101 MHz, acetone-d6) δ: 139.3 (s), 128.9 (d, 2C), 128.1 (d, 2C), 128.0 (d), 97.7 (d), 84.8 (d), 81.5 (d), 80.8 (d), 77.8 (d), 74.1 (d), 73.8 (d), 72.2 (t), 71.1 (d), 70.6 (d), 70.3 (d), 65.2 (t), 26.5 (q, 3C), 26.4 (q, 3C), 26.3 (q, 3C), 26.2 (q, 3C), 26.2 (q, 3C), 24.7 (t), 19.0 (q), 19.0 (s), 18.8 (s), 18.7 (s), 18.6 (s), 18.5 (s), 15.6 (q), −3.3 (q), −4.1 (q), −4.1 (q), −4.2 (q), −4.2 (q), −4.3 (q), −4.3 (q), −4.5 (q), −5.0 (q), −5.0 (q). HRMS m/z [M + Na]+ Calcd for C51H102O9SSi5Na 1053.5989. Found 1053.5939.

Ethyl 2-O-(2-O-Bn-3,4-di-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-1-thio-β-D-glucopyranoside (22e)

In a reaction similar to that described for the synthesis of 22a, the use of 34e (2.50 g, 3.73 mmol), MeOH (37 mL), NaOMe (200 mg, 3.73 mmol), DMF (37 mL), 2,6-lutidine (8.00 g, 74.6 mmol), and TBSOTf (14.8 g, 56.0 mmol) provided a crude product containing 22e. The crude product was purified by CC (SiO2 100 g, hexane/EtOAc = 1/0 to 20/1) to afford 22e (4.3 g, 100%, for 2 steps) as a colorless syrup. Among the following spectral data for 22e, enough signals were not observed due to several extremely broad signals. Observations at 40, 50, and 60 °C or change of the solvent to CDCl3 and benzene-d6 gave null effect to sharpen the signals. Data for 22e: [α]D25 −44.2 (c 1.50, CHCl3). IR (ZnSe) 2955, 2930, 2886, 2857, 1474, 1258, 1102, 868, 777 cm−1. 1H-NMR (400 MHz, acetone-d6) δ: 7.43–7.39 (m, 2H), 7.38–7.32 (m, 1H), 7.31–7.26 (m, 2H), 5.11 (br d, J = 1.6 Hz, rha-H1), 4.87 (d, J = 8.5 Hz, glc-H1), 4.76 (d, J = 11.9 Hz, 1H), 4.68 (d, J = 11.9 Hz, 1H), 4.09 (m, 1H, rha-H3), 4.04–4.02 (m, 2H, glc-H3, glc-H5), 3.92 (m, 1H, rha-H5), 3.85–3.74 (m, 5H, glc-H4, H6, H6, H2, rha-H4), 3.71 (br s, 1H, rha-H2), 2.78–2.59 (m, 2H), 1.29 (t, J = 7.6 Hz, 3H), 1.24 (d, J = 6.4 Hz, 3H, rha-H6), 0.97 (s, 9H), 0.93 (s, 36H), 0.18 (s, 3H), 0.17 (s, 3H), 0.16 (s, 3H), 0.15 (s, 3H), 0.15 (s, 3H), 0.14 (s, 3H), 0.13 (s, 6H), 0.11 (s, 6H). 13C-NMR (101 MHz, acetone-d6) δ: 140.6 (s), 129.8 (d, 2C), 129.0 (d), 128.8 (d, 2C), 85.2 (d), 82.3 (d), 75.1 (d), 74.4 (t), 72.1 (d), 71.9 (d), 65.8 (t), 33.1 (t), 27.7 (q, 3C), 27.4 (q, 3C), 27.1 (q, 6C), 27.0 (q, 3C), 25.7 (t), 24.0 (t), 19.8 (s), 19.7 (s), 19.5 (s), 19.3 (s), 19.3 (s), 16.4 (q), 15.1 (q), −2.7 (q), −2.9 (q), −3.4 (q, 3C), −3.5 (q), −3.7 (q), −4.2 (q, 3C). HRMS m/z [M + Na]+ Calcd for C51H102O9SSi5Na 1053.5989. Found 1053.5972.

Cholestanyl 2-O-(2,4-Di-O-Bn-3-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-D-glucopyranoside (35a)

To a mixture of 22a (130 mg, 129 µmol), cholestanol (60.2 mg, 155 µmol), Msv 4A (130 mg), and 2,6-lutidine (27.7 mg, 258 µmol) in CH2Cl2 (1.5 mL) was added MeOTf (84.8 mg, 517 µmol). The mixture was stirred for 6 h at r.t., and the reaction was quenched by Et3N (100 µL). The mixture was diluted with CH2Cl2 and filtered through a Celite pad. The filtrate was successively washed with H2O and brine. After the general drying procedure, the mixture was purified by CC (SiO2 3 g, hexane/EtOAc = 1/0 to 50/1) to afford an anomeric mixture of 35a (115 mg, 67% yield, α/β = 26/74) as a colorless syrup. The anomeric ratio was determined by integral of the H-1 peak of the 1H-NMR spectrum. A part of the mixture was further separated by HPLC (column, YMC-Pack R&D SIL R-SIL-5-A, 250 × 4.6 mm; eluent, hexane/EtOAc 98/2; tR: 9.2 min for the β-isomer, 13.4 min for the α-isomer). Data for 35a-α: [α]D24 +18.5 (c 1.04, CHCl3). IR (ATR) 2951, 2929, 2856, 1738, 1472, 1386, 1374, 1362, 1251, 1216, 1089, 1063, 837 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.39–7.25 (m, 10H), 4.97 (d, J = 3.9 Hz, 1H, glc-H1), 4.95 (d, J = 11.5 Hz, 1H), 4.92 (br s, 1H, rha-H1), 4.90 (d, J = 11.9 Hz, 1H), 4.62 (d, J = 11.9 Hz, 1H), 4.59 (d, J = 11.5 Hz, 1H), 4.13 (dd, J = 9.2, 2.5 Hz, 1H, rha-H3), 3.94 (dd, J = 8.1, 8.1 Hz, 1H, glc-H6), 3.85–3.79 (m, 3H, rha-H2, H5, glc-H3), 3.70–3.58 (m, 2H, glc-H4, H5), 3.53 (m, 1H, agl-H3), 3.51 (dd, 1H, J = 9.2, 9.2 Hz, rha-H4), 3.44 (dd, J = 4.2, 3.9 Hz, 1H, glc-H2), 3.43 (dd, J = 8.5, 8.1 Hz, 1H, glc-H6), 1.22 (d, J = 6.2 Hz, 3H, rha-H6), 0.92 (d, J = 6.4 Hz, 3H, agl-H21), 0.92 (s, 9H), 0.91 (s, 9H), 0.90 (s, 9H), 0.89 (s, 9H), 0.87 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.87 (d, J = 6.4 Hz, 3H, agl-H26 or H27), 0.80 (s, 3H, agl-H18 or H19), 0.67 (s, 3H, agl-H18 or H19), 0.14 (s, 3H), 0.13 (s, 3H), 0.12 (s, 3H), 0.10 (s, 3H), 0.10 (s, 3H), 0.05 (s, 6H), 0.04 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ: 139.4 (s), 139.2 (s), 128.4 (d, 2C), 128.2 (d, 2C), 127.9 (d, 2C), 127.6 (d, 2C), 127.5 (d), 127.2 (d), 100.5 (d), 96.4 (d), 81.4 (d), 80.2 (d), 78.7 (d), 77.0 (d), 74.6 (t), 74.3 (t), 73.8 (d), 73.7 (d), 73.5 (d), 73.4 (d), 68.9 (d), 63.5 (t), 56.7 (d), 56.5 (d), 54.6 (d), 45.2 (d), 42.8 (s), 40.3 (t), 39.7 (t), 37.3 (t), 36.4 (t), 36.4 (t), 36.0 (d), 35.7 (s), 35.7 (d), 32.4 (t), 29.0 (t), 28.5 (t), 28.2 (d), 28.2 (t), 26.8 (q, 3C), 26.6 (q, 3C), 26.3 (q, 3C), 26.2 (q, 3C), 24.4 (t), 24.0 (t), 23.0 (q), 22.8 (q), 21.5 (t), 18.9 (q), 18.6 (s), 18.4 (s), 18.3 (s), 18.2 (s), 18.1 (q), 12.4 (q), 12.3 (q), −1.8 (q), −2.0 (q), −2.7 (q), −3.5 (q), −4.2 (q), −4.5 (q), −4.8 (q), −5.0 (q). HRMS m/z [M + Na]+ Calcd for C77H136O10Si4Na 1355.9108. Found 1355.9122. Data for 35a-β: [α]D23 −19.4 (c 2.79, CHCl3). IR (ATR) 2949, 2928, 2856, 1733, 1471, 1387, 1362, 1253, 1215, 1091, 834 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.40–7.22 (m, 10H), 4.903 (d, J = 7.1 Hz, 1H, glc-H1), 4.893 (d, J = 12.6 Hz, 1H), 4.889 (d, J = 11.7 Hz, 1H), 4.86 (d, J = 1.1 Hz, 1H, rha-H1), 4.71 (d, J = 12.6 Hz, 1H), 4.62 (d, J = 11.7 Hz, 1H), 4.04 (dq, J = 9.6, 6.2 Hz, 1H, rha-H5), 4.01 (dd, J = 9.2, 3.0 Hz, 1H, rha-H3), 3.90 (dd, J = 3.4, 1.0 Hz, 1H, glc-H4), 3.78 (dd, J = 8.2, 5.0 Hz, 1H, glc-H6), 3.76 (d, J = 8.2 Hz, 1H, glc-H6), 3.71 (dd, J = 5.0, 3.4 Hz, 1H, glc-H5), 3.68 (dd, J = 3.0, 1.1 Hz, 1H, rha-H2), 3.64 (d, J = 7.1 Hz, 1H, glc-H2), 3.56 (m, 1H, agl-H3), 3.52 (d, J = 1.0 Hz, 1H, glc-H3), 3.49 (dd, J = 9.6, 9.2 Hz, 1H, rha-H4), 1.22 (d, J = 6.2 Hz, 3H, rha-H6), 0.94 (s, 9H), 0.92–0.86 (m, 27H, agl-H21, H26, H27, t-Bu), 0.82 (s, 9H), 0.73 (s, 3H, agl-H18 or H19), 0.66 (s, 3H, agl-H18 or H19), 0.09 (s, 3H), 0.07 (s, 3H), 0.05 (s, 3H), 0.05 (s, 3H), 0.04 (s, 6H), 0.03 (s, 3H), -0.06 (s, 3H).13C-NMR (101 MHz, CDCl3) δ: 139.3 (s), 138.9 (s), 128.4 (d, 2C), 128.1 (d, 2C), 127.8 (d, 2C), 127.6 (d), 127.1 (d, 2C), 127.0 (d), 97.2 (d), 94.6 (d), 82.5 (d), 81.6 (d), 79.1 (d), 78.0 (d), 77.1 (d), 74.9 (t), 74.6 (d), 73.6 (t), 73.5 (d), 69.8 (d), 68.0 (d), 64.1 (t), 56.6 (d), 56.4 (d), 54.6 (d), 44.9 (d), 42.7 (s), 40.2 (t), 39.6 (t), 37.2 (t), 36.3 (t), 35.9 (d), 35.8 (s), 35.6 (d), 34.3 (t), 32.3 (t), 29.5 (t), 29.0 (t), 28.4 (t), 28.1 (d), 26.2 (q, 3C), 26.0 (q, 3C), 25.9 (q, 3C), 29.8 (q, 3C), 24.3 (t), 23.9 (t), 22.9 (q), 22.7 (q), 21.3 (t), 18.8 (q), 18.3 (s), 18.1 (s), 18.1 (s), 17.8 (s), 17.7 (q), 12.3 (q), 12.2 (q), −4.2 (q), −4.4 (q), −4.5 (q), −4.7 (q, 3C), −5.2 (q, 2C). HRMS m/z [M + Na]+ Calcd for C77H136O10Si4Na 1355.9108. Found 1355.9122.

Cholestanyl 2-O-(2,3-Di-O-Bn-4-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-D-glucopyranoside (35b)

In a reaction similar to that described for the synthesis of 35a, the use of 22b (120 mg, 120 µmol), cholestanol (55.9 mg, 144 µmol), Msv 4A (130 mg), 2,6-lutidine (25.5 mg, 238 µmol), CH2Cl2 (1.2 mL), and MeOTf (78.3 mg, 477 µmol) provided a crude product containing 35b. The reaction time was 5 h. The crude product was purified by CC (SiO2 4 g, hexane/EtOAc = 50/1 to 30/1) to afford an anomeric mixture of 35b (94.6 mg, 60% yield, α/β = 26/74) as a colorless syrup. The anomeric ratio was determined by integral of the H-1 peak of the 1H-NMR spectrum. A part of the mixture was further separated by HPLC (column, YMC-Pack R&D SIL R-SIL-5-A, 250 × 4.6 mm; eluent, hexane/EtOAc 98/2; tR: 6.9 min for the β-isomer, 10.0 min for the α-isomer). Data for 35b-α: [α]D24 +19 (c 0.74, CHCl3). IR (ATR) 2951, 2929, 2856, 1472, 1463, 1252, 1216, 1100, 1062, 1028, 836 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.36–7.22 (m, 10H), 5.01 (d, J = 3.4 Hz, 1H, glc-H1), 4.90 (d, J = 1.4 Hz, 1H, rha-H1), 4.71 (d, J = 11.7 Hz, 1H), 4.64 (d, J = 11.9 Hz, 1H), 4.61 (d, J = 11.9 Hz, 1H), 4.58 (d, J = 11.7 Hz, 1H), 4.02 (dd, J = 2.1, 2.1 Hz, 1H, glc-H4), 3.96 (dd, J = 8.8, 8.5 Hz, 1H, rha-H4), 3.84 (dq, J = 8.8, 7.3 Hz, 1H, rha-H5), 3.78 (dd, J = 5.7, 2.1 Hz, 1H, glc-H3), 3.77 (dd, J = 8.7, 8.5 Hz, 1H, glc-H6), 3.69–3.62 (m, 3H, glc-H2, H5, rha-H2), 3.55 (m, 1H, agl-H3), 3.46 (dd, J = 9.0, 8.5 Hz, 1H, glc-H6), 3.35 (dd, J = 8.5, 3.4 Hz, 1H, rha-H3), 1.23 (d, J = 7.3 Hz, 3H, rha-H6), 0.92–0.91 (m, 21H, agl-H21, t-Bu), 0.88–0.85 (m, 24H, agl-H26, H27, t-Bu), 0.82 (s, 3H, agl-H18 or H19), 0.66 (s, 3H, agl-H18 or H19), 0.13 (s, 3H), 0.11 (s, 3H), 0.09 (s, 3H), 0.09 (s, 3H), 0.07 (s, 3H), 0.06 (s, 3H), 0.06 (s, 3H), 0.00 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ: 138.9 (s), 138.8 (s), 128.3 (d, 4C), 127.4 (d, 4C), 127.3 (d, 2C), 101.0 (d), 96.2 (d), 80.8 (d), 80.5 (d), 76.7 (d), 75.6 (d), 73.5 (d), 73.4 (d), 73.4 (d), 73.3 (t), 73.1 (d), 71.9 (t), 69.7 (d), 63.2 (t), 56.6 (d), 56.4 (d), 54.5 (d), 45.1 (d), 42.7 (s), 40.2 (t), 39.6 (t), 37.3 (t), 37.2 (t), 36.2 (t), 35.9 (d), 35.6 (s), 35.6 (d), 32.2 (t), 28.9 (t), 28.4 (t), 28.1 (d), 27.8 (t), 26.7 (q, 3C), 26.5 (q, 3C), 26.1 (q, 3C), 26.0 (q, 3C), 24.3 (t), 23.9 (t), 22.9 (q), 22.6 (q), 21.3 (t), 18.8 (q), 18.5 (q), 18.5 (s), 18.3 (s), 18.2 (s), 18.2 (s), 12.4 (q), 12.2 (q), −1.7 (q), −2.0 (q), −2.9 (q), −3.4 (q), −3.6 (q), −4.4 (q), −4.9 (q), −5.1 (q). HRMS m/z [M + Na]+ Calcd for C77H136O10Si4Na 1355.9108. Found 1355.9080. Data for 35b-β: [α]D23 −25.0 (c 1.78, CHCl3). IR (ATR) 3013, 2953, 2929, 2856, 1471, 1464, 1254, 1215, 1093, 1056, 836 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.38–7.21 (m, 10H), 4.88 (br s, 1H, rha-H1), 4.86 (d, J = 6.9 Hz, 1H, glc-H1), 4.75 (d, J = 12.6 Hz, 1H), 4.67 (d, J = 12.6 Hz, 1H), 4.52 (d, J = 12.0 Hz, 1H), 4.48 (d, J = 12.0 Hz, 1H), 3.91 (dq, J = 9.2, 6.2 Hz, 1H, rha-H5), 3.86 (d, J = 3.2 Hz, 1H, glc-H4), 3.78 (dd, J = 9.2, 9.2 Hz, 1H, rha-H4), 3.75–3.69 (m, 4H, glc-H5, H6, H6, rha-H2), 3.66 (d, J = 3.2 Hz, 1H, glc-H3), 3.60 (d, J = 6.9 Hz, 1H, glc-H2), 3.54 (m, 1H, agl-H3), 3.54 (dd, J = 9.2, 2.3 Hz, 1H, rha-H3), 1.25 (d, J = 6.2 Hz, 3H, rha-H6), 0.92–0.84 (m, 36H, agl-H21, H26, H27, t-Bu), 0.81 (s, 9H), 0.79 (s, 3H, agl-H18 or H19), 0.66 (s, 3H, agl-H18 or H19), 0.09 (s, 3H), 0.08 (s, 3H), 0.07 (s, 3H), 0.05 (s, 3H), 0.04 (s, 6H), 0.01 (s, 3H), -0.07 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ: 138.8 (s), 138.7 (s), 128.4 (d, 2C), 128.3 (d, 2C), 127.9 (d, 2C), 127.7 (d), 127.4 (d, 2C), 127.3 (d), 97.7 (d), 95.3 (d), 82.3 (d), 80.7 (d), 78.2 (d), 78.2 (d), 74.9 (d), 74.2 (d), 73.2 (d), 72.9 (t), 71.7 (t), 69.7 (d), 69.4 (d), 64.1 (t), 56.7 (d), 56.4 (d), 54.6 (d), 44.9 (d), 42.7 (s), 40.2 (t), 39.6 (t), 37.3 (t), 36.3 (t), 35.9 (d), 35.8 (s), 35.6 (d), 34.5 (t), 32.3 (t), 29.6 (t), 29.0 (t), 28.4 (t), 28.1 (d), 26.1 (q, 3C), 26.0 (q, 3C), 26.0 (q, 3C), 25.8 (q, 3C), 24.3 (t), 23.9 (t), 22.9 (q), 22.7 (q), 21.3 (t), 18.8 (q), 18.4 (s), 18.3 (s), 18.2 (s), 18.1 (s), 17.8 (q), 12.6 (q), 12.2 (q), −3.6 (q), −4.3 (q), −4.5 (q), −4.6 (q, 3C), −5.2 (q, 2C). HRMS m/z [M + Na]+ Calcd for C77H136O10Si4Na 1355.9108. Found 1355.9081.

Cholestanyl 2-O-(4-O-Bn-2,3-di-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-D-glucopyranoside (35c)

In a reaction similar to that described for the synthesis of 35a, the use of 22c (99.0 mg, 96.1 µmol), cholestanol (44.8 mg, 115 µmol), Msv 4A (99 mg), 2,6-lutidine (41.2 mg, 384 µmol), CH2Cl2 (1 mL), and MeOTf (126 mg, 768 µmol) provided a crude product containing 35c. The crude product was purified by CC (SiO2 6 g, hexane/EtOAc = 1/0 to 50/1) to afford an anomeric mixture of 35c (103 mg, 79% yield, α/β = 16/84) as a colorless syrup. The anomeric ratio was determined by integral of the H-1 peak of the 1H-NMR spectrum. We could not separate the mixture even with HPLC (both normal and reverse phases). Partial data of 35c: 1H-NMR (400 MHz, CDCl3) δ: 4.98 (d, J = 3.6 Hz, glc-H1 of the α-isomer), 4.91 (d, J = 7.2 Hz, 1H, glc-H1 of the β-isomer), 4.74 (br d, J = 1.2 Hz, 1H, rha-H1 of the β-isomer), 4.65 (br d, J = 1.2 Hz, rha-H1 of the α-isomer). 13C-NMR (101 MHz, CDCl3) δ: 102.5 (d, rha-C1 of the α-isomer), 97.6 (d, glc-C1 of the β-isomer), 96.6 (d, glc-C1 of the α-isomer), 95.9 (d, rha-C1 of the β-isomer).

Cholestanyl 2-O-(3-O-Bn-2,4-di-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-D-glucopyranoside (35d)

In a reaction similar to that described for the synthesis of 35a, the use of 22d (94.1 mg, 91.3 µmol), cholestanol (42.6 mg, 110 µmol), Msv 4A (94 mg), 2,6-lutidine (19.6 mg, 183 µmol), CH2Cl2 (1 mL), and MeOTf (59.9 mg, 365 µmol) provided a crude product containing 35d. The reaction time was 2 h. The crude product was purified by CC (SiO2 10 g, hexane/Et2O = 100/1 to 50/1) to afford an anomeric mixture of 35d (80.7 mg, 65% yield, α/β = 21/79) as a colorless syrup. The anomeric ratio was determined by integral of the H-1 peak of the 1H-NMR spectrum. We could not separate the mixture even with HPLC (both normal and reverse phases). Partial data of 35d: 1H-NMR (400 MHz, CDCl3) δ: 5.03 (d, J = 2.8 Hz, glc-H1 of the α-isomer), 4.90 (d, J = 6.8 Hz, 1H, glc-H1 of the β-isomer), 4.78 (br s, rha-H1 of the β-isomer), 4.67 (br s, rha-H1 of the α-isomer). 13C-NMR (101 MHz, CDCl3) δ: 103.2 (d, rha-C1 of the α-isomer), 98.0 (d, glc-C1 of the β-isomer), 96.8 (d, rha-C1 of the β-isomer), 96.6 (d, glc-C1 of the α-isomer).

Cholestanyl 2-O-(2-O-Bn-3,4-di-O-TBS-α-L-rhamnopyranosyl)-3,4,6-tri-O-TBS-β-D-glucopyranoside (35e)

In a reaction similar to that described for the synthesis of 35a, the use of 22e (318 mg, 308 µmol), cholestanol (144 mg, 370 µmol), Msv 4A (300 mg), 2,6-lutidine (66.0 mg, 616 µmol), CH2Cl2 (3 mL), and MeOTf (202 mg, 1.23 mmol) provided a crude product containing 35e. The reaction time was 10 h. The crude product was purified by CC (SiO2 15 g, hexane/Et2O = 75/1) to afford an anomeric mixture of 35e (222 mg, 53% yield, α/β ≤1/99) as a colorless syrup. Data for 35e: [α]D23 −14.8 (c 7.09, CHCl3). IR (ATR) 2951, 2931, 2857, 1464, 1255, 1215, 1096, 1053, 867, 836 cm−1. 1H-NMR (400 MHz, CDCl3, 60 °C) δ: 7.37 (d, J = 7.6 Hz, 2H), 7.31 (dd, J = 7.6, 7.1 Hz, 2H), 7.24 (t, J = 7.1 Hz, 1H), 4.95 (d, J = 1.8 Hz, 1H, rha-H1), 4.92 (d, J = 7.1 Hz, 1H, glc-H1), 4.75 (d, J = 12.4 Hz, 1H), 4.65 (d, J = 12.4 Hz, 1H), 3.95 (dd, J = 8.2, 2.3 Hz, 1H, rha-H3), 3.91 (d, J = 3.0 Hz, 1H, glc-H4), 3.85 (dq, J = 8.5, 6.4 Hz, 1H, rha-H5), 3.82 (d, J = 3.0 Hz, 1H, glc-H3), 3.80–3.70 (m, 4H, glc-H5, H6, H6, rha-H4), 3.65 (d, J = 7.1 Hz, 1H, glc-H2), 3.61 (dd, J = 2.3, 1.8 Hz, rha-H2), 3.59 (m, 1H, agl-H3), 1.22 (d, J = 6.4 Hz, 3H, rha-H6), 0.95 (s, 9H), 0.92 (s, 9H), 0.91 (s, 9H), 0.90 (s, 18H), 0.93–0.87 (m, 9H, agl-H21, H26, H27), 0.81 (s, 3H, agl-H18 or H19), 0.68 (s, 3H, agl-H18 or H19), 0.14 (s, 3H), 0.11 (s, 3H), 0.11 (s, 6H), 0.10 (s, 3H), 0.09 (s, 3H), 0.08 (s, 3H), 0.07 (s, 3H), 0.07 (s, 3H), 0.05 (s, 3H). 13C-NMR (101 MHz, CDCl3) δ: 139.0 (s), 128.2 (d, 2C), 127.4 (d, 2C), 127.4 (d), 97.3 (d), 94.2 (d), 82.3 (d), 80.5 (d), 77.9 (d), 77.6 (d), 77.3 (d), 74.4 (d), 73.7 (d), 73.3 (t), 70.0 (d), 69.7 (d), 64.1 (t), 56.5 (d), 56.3 (d), 54.6 (d), 44.9 (d), 42.6 (s), 40.1 (t), 39.5 (t), 37.2 (t), 36.2 (t), 35.8 (d), 35.7 (s), 35.5 (d), 34.3 (t), 32.2 (t), 29.5 (t), 28.9 (t), 28.3 (t), 28.0 (d), 26.7 (q, 2C), 26.3 (q, 2C), 25.9 (q, 4C), 25.8 (q, 3C), 25.8 (q, 4C), 24.2 (t), 23.8 (t), 22.8 (q), 22.6 (q), 21.2 (t), 18.7 (q), 18.4 (s), 18.3 (q), 18.3 (s), 18.1 (s), 18.0 (s), 17.8 (s), 12.5 (q), 12.1 (q), −2.4 (q), −3.3 (q), −3.8 (q, 2C), −4.6 (q, 2C), −4.7 (q), −4.8 (q), −5.3 (q, 2C). HRMS m/z [M + Na]+ Calcd for C76H144O10Si5Na 1379.9503. Found 1379.9488.

Cholestanyl 3,4,6-Tri-O-Ac-2-O-(3-O-Ac-2,4-di-O-Bn-α-L-rhamnopyranosyl)-β-D-glucopyranoside (36a)

A mixture of 35a-β (55.7 mg, 41.8 µmol) and TBAF (1.0 M solution in THF, 0.46 mL, 0.46 mmol) in THF (0.42 mL) was stirred for 2 h at r.t. After concentration of the reaction mixture, to the residue were added pyridine (0.42 mL), Ac2O (34.1 mg, 334 µmol), and DMAP (4.1 mg, 33 µmol). The mixture was heated at reflux for 3 h. After the mixture was cooled to r.t., the mixture was diluted with EtOAc (20 mL). The EtOAc solution was successively washed with H2O and brine. After the general drying procedure, the crude product was found to contain small amount of incompletely acetylated compounds. After concentration, to the crude product were added pyridine (0.42 mL), Ac2O (34.1 mg, 334 µmol), and DMAP (4.1 mg, 33 µmol). The mixture was heated at reflux for 1 h. After the mixture was cooled to r.t., H2O (5 mL) was added to the mixture. The aqueous mixture was extracted with EtOAc. The combined organic layer was successively washed with H2O and brine. After the general drying procedure, the mixture was purified by CC (SiO2 2 g, hexane/EtOAc = 5/1 to 3/1) to give 36a (22.6 mg, 52% yield) as a colorless syrup. Data for 36a: [α]D25 +3.69 (c 1.13, CHCl3). IR (ATR) 3020, 2933, 2867, 1748, 1456, 1365, 1232, 1217, 1098, 1078, 1038 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.36–7.24 (m, 10H), 5.20 (dd, J = 9.4, 9.2 Hz, 1H, glc-H3), 5.11 (dd, J = 9.4, 3.4 Hz, 1H, rha-H3), 4.96 (dd, J = 9.9, 9.4 Hz, 1H, glc-H4), 4.95 (d, J = 1.8 Hz, 1H, rha-H1), 4.69 (d, J = 11.2 Hz, 1H), 4.60 (d, J = 11.2 Hz, 1H), 4.60 (d, J = 12.1 Hz, 1H), 4.54 (d, J = 7.8 Hz, 1H, glc-H1), 4.47 (d, J = 12.1 Hz, 1H), 4.27 (dd, J = 12.1, 5.0 Hz, 1H, glc-H6), 4.25 (dq, J = 9.6, 6.4 Hz, 1H, rha-H5), 4.07 (dd, J = 12.1, 2.3 Hz, 1H, glc-H6), 3.77 (dd, J = 3.4, 1.8 Hz, 1H, rha-H2), 3.74 (dd, J = 9.2, 7.8 Hz, 1H, glc-H2), 3.65 (ddd, J = 9.9, 5.0, 2.3 Hz, 1H, glc-H5), 3.62 (m, 1H, agl-H3), 3.56 (dd, J = 9.6, 9.4 Hz, 1H, rha-H4), 2.08 (s, 3H), 2.00 (s, 3H), 1.94 (s, 3H), 1.93 (s, 3H), 1.30 (d, J = 6.4 Hz, 3H, rha-H6), 0.89 (d, J = 6.6 Hz, 3H, agl-H21), 0.86 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.85 (d, J = 6.4 Hz, 3H, agl-H26 or H27), 0.63 (s, 6H, agl-H18, H19). 13C-NMR (101 MHz, CDCl3) δ: 170.7 (s), 170.0 (s), 169.9 (s), 169.7 (s), 138.5 (s), 137.7 (s), 128.4 (d, 2C), 128.2 (d, 2C), 127.9 (d), 127.9 (d, 2C), 127.5 (d, 3C), 99.7 (d), 97.7 (d), 79.2 (d), 79.0 (d), 76.2 (d), 75.6 (d), 74.7 (t), 74.3 (d), 73.4 (d), 73.1 (t), 71.4 (d), 68.9 (d), 68.0 (d), 62.3 (t), 56.5 (d), 56.3 (d), 54.3 (d), 44.7 (d), 42.6 (s), 40.0 (t), 39.5 (t), 37.0 (t), 36.2 (t), 35.8 (d), 35.5 (s), 35.4 (d), 33.9 (t), 32.1 (t), 29.3 (t), 28.6 (t), 28.3 (t), 28.0 (d), 24.2 (t), 23.8 (t), 22.8 (q), 22.6 (q), 21.2 (t), 21.1 (q), 20.8 (q, 2C), 20.7 (q), 18.7 (q), 17.9 (q), 12.1 (q), 12.1 (q). HRMS m/z [M + Na]+ Calcd for C61H88O14Na 1067.6072. Found 1067.6075.

Cholestanyl 3,4,6-Tri-O-Ac-2-O-(4-O-Ac-2,3-di-O-Bn-α-L-rhamnopyranosyl)-β-D-glucopyranoside (36b)

In a reaction similar to that described for the synthesis of 36a, the use of 35b-β (35.5 mg, 26.6 µmol), TBAF (1.0 M solution in THF, 0.26 mL, 0.26 mmol), THF (0.3 mL), pyridine (0.3 mL), Ac2O (22 mg, 210 µmol), and DMAP (2.6 mg, 21 µmol) provided a crude product containing 36b. The reaction time was 1.5 h for the second step. The crude product was purified by CC (SiO2 2 g, hexane/EtOAc = 5/1 to 3/1) to give 36b (19.3 mg, 69% yield) as a colorless syrup. Data for 36b: [α]D25 −3.9 (c 0.98, CHCl3). IR (ATR) 3020, 2933, 2867, 1742, 1541, 1455, 1365, 1234, 1121, 1088, 1037 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.35–7.24 (m, 10H), 5.21 (dd, J = 9.9, 9.6 Hz, 1H, rha-H4), 5.18 (dd, J = 9.4, 9.4 Hz, 1H, glc-H3), 4.96 (dd, J = 9.9, 9.4 Hz, 1H, glc-H4), 4.95 (d, J = 1.4 Hz, 1H, rha-H1), 4.70 (d, J = 12.4 Hz, 1H), 4.65 (d, J = 12.4 Hz, 1H), 4.55 (d, J = 12.1 Hz, 1H), 4.48 (d, J = 7.8 Hz, 1H, glc-H1), 4.43 (d, J = 12.1 Hz, 1H), 4.26 (dd, J = 12.2, 5.0 Hz, 1H, glc-H6), 4.25 (dq, J = 9.9, 6.2 Hz, 1H, rha-H5), 4.08 (dd, J = 12.2, 2.3 Hz, 1H, glc-H6), 3.75 (dd, J = 9.4, 7.8 Hz, 1H, glc-H2), 3.72 (dd, J = 3.0, 1.4 Hz, 1H, rha-H2), 3.70 (dd, J = 9.6, 3.0 Hz, 1H, rha-H3), 3.64 (ddd, J = 9.9, 5.0, 2.3 Hz, 1H, glc-H5), 3.62 (m, 1H, agl-H6), 2.07 (s, 3H), 2.00 (s, 3H), 1.99 (s, 3H), 1.91 (s, 3H), 1.17 (d, J = 6.2 Hz, 3H, rha-H6), 0.90 (d, J = 6.4 Hz, 3H, agl-H21), 0.86 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.86 (d, J = 6.4 Hz, 3H, agl-H-26 or H27), 0.79 (s, 3H, agl-H18 or H19), 0.65 (s, 3H, agl-H18 or H19). 13C-NMR (101 MHz, CDCl3) δ: 170.9 (s), 170.3 (s), 170.1 (s), 169.8 (s), 138.5 (s), 138.3 (s), 128.6 (d, 2C), 128.5 (d, 2C), 128.1 (d, 2C), 127.9 (d), 127.8 (d), 127.5 (d, 2C), 99.6 (d), 98.4 (d), 78.8 (d), 77.3 (d), 75.9 (d), 74.5 (d), 74.1 (d), 73.3 (d), 73.2 (t), 72.0 (t), 71.7 (d), 69.0 (d), 67.2 (d), 62.4 (t), 56.7 (d), 56.5 (d), 54.6 (d), 44.8 (d), 42.8 (s), 40.2 (t), 39.7 (t), 37.2 (t), 36.4 (t), 36.0 (d), 35.8 (s), 35.7 (d), 34.2 (t), 32.3 (t), 29.5 (t), 29.2 (t), 28.5 (t), 28.2 (d), 24.4 (t), 24.0 (t), 23.0 (q), 22.8 (q), 21.4 (t), 21.3 (q), 21.0 (q), 21.0 (q), 20.8 (q), 18.9 (q), 17.6 (q), 12.4 (q), 12.3 (q). HRMS m/z [M + Na]+ Calcd for C61H88O14Na 1067.6072. Found 1067.6056.

Cholestanyl 3,4,6-Tri-O-Ac-2-O-(2,3-di-O-Ac-4-O-Bn-α-L-rhamnopyranosyl)-D-glucopyranoside (36c)

In a reaction similar to that described for the synthesis of 36a, the use of 35c (16/84 α/β mixture, 70.6 mg, 52.0 µmol), TBAF (1.0 M solution in THF, 1.0 mL, 1.0 mmol), THF (0.5 mL), pyridine (0.5 mL), Ac2O (53 mg, 0.52 mmol), and DMAP (5.1 mg, 42 µmol) provided a crude product containing 36c. The reaction time was 11 h for the first step and 9 h for the second step. The reaction temperature for the second step was 80 °C. The crude product was purified by CC (SiO2 2 g, hexane/EtOAc = 10/1 to 2/1) to give 36c (37.5 mg, 72% yield) as a mixture of anomeric isomers (α/β = 17/83). The mixture could not be separated by HPLC (ODS). Data for the major product (36c-β): 1H-NMR (400 MHz, CDCl3) δ: 7.35–7.24 (m, 5H, Bn), 5.25 (dd, J = 9.6, 3.2 Hz, 1H, rha-H3), 5.22 (dd, J = 9.6, 9.4 Hz, 1H, glc-H3), 5.00 (dd, J = 3.2, 1.8 Hz, 1H, rha-H2), 4.94 (dd, J = 9.4, 8.9 Hz, 1H, glc-H4), 4.92 (d, J = 1.8 Hz, 1H, rha-H1), 4.68 (d, J = 11.2 Hz, 1H), 4.60 (d, J = 11.2 Hz, 1H), 4.57 (d, J = 7.8 Hz, 1H, glc-H1), 4.34 (dq, J = 9.6, 6.2 Hz, 1H, rha-H5), 4.26 (dd, J = 12.1, 5.0 Hz, 1H, glc-H6), 4.07 (dd, J = 12.1, 2.3 Hz, 1H, glc-H6), 3.71 (dd, J = 9.6, 7.8 Hz, 1H, glc-H2), 3.66 (m, 1H, glc-H5), 3.65 (m, 1H, agl-H3), 3.48 (dd, J = 9.6, 9.6 Hz, 1H, rha-H4), 2.11 (s, 3H), 2.06 (s, 3H), 2.04 (s, 3H), 2.00 (s, 3H), 1.97 (s, 3H), 1.30 (d, J = 6.2 Hz, 3H, rha-H6), 0.90 (d, J = 6.4 Hz, 3H, agl-H21), 0.87 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.86 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.64 (s, 3H, agl-H18 or H19), 0.63 (s, 3H, agl-H18 or H19).

Cholestanyl 3,4,6-Tri-O-Ac-2-O-(2,4-di-O-Ac-3-O-Bn-α-L-rhamnopyranosyl)-D-glucopyranoside (36d)

In a reaction similar to that described for the synthesis of 36a, the use of 35d (21/79 α/β mixture, 84.7 mg, 62.4 µmol), TBAF (1.0 M solution in THF, 1.2 mL, 1.2 mmol), THF (0.6 mL), pyridine (0.6 mL), Ac2O (64 mg, 0.62 mmol), and DMAP (2.5 mg, 20 µmol) provided a crude product containing 36d. The reaction time and temperature were 4 h and reflux temperature of THF for the first step, and 11 h and 80 °C for the second step, respectively. The crude product was purified by CC (SiO2 2 g, hexane/EtOAc = 5/1 to 2/1) to give 36d (50.3 mg, 81% yield) as a mixture of anomeric isomers. Successive purification with GPC and HPLC (column, UMC-Pack R&D SIL, 250 × 4.6 mm; eluent, hexane/EtOAc 75/25) separated the anomeric isomers. Data for 36d-α: [α]D23 +36 (c 0.11, CHCl3). IR (ATR) 2922, 2852, 1748, 1457, 1372, 1225, 1138, 1090, 1042, 759 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.34–7.25 (m, 5H), 5.43 (dd, J = 10.0, 9.6 Hz, 1H, glc-H3), 5.12 (dd, J = 3.4, 1.6 Hz, 1H, rha-H2), 5.02 (dd, J = 9.9, 9.6 Hz, 1H, glc-H4), 4.99 (d, J = 3.2 Hz, 1H, glc-H1), 4.96 (dd, J = 9.6, 9.6 Hz, 1H, rha-H4), 4.84 (d, J = 1.6 Hz, 1H, rha-H1), 4.60 (d, J = 12.1 Hz, 1H), 4.42 (d, J = 12.1 Hz, 1H), 4.24 (dd, J = 12.0, 4.8 Hz, 1H, glc-H6), 4.10 (ddd, J = 9.9, 4.8, 2.3 Hz, glc-H5), 4.07 (dd, J = 12.0, 2.3 Hz, 1H, glc-H6), 3.76 (dq, J = 9.6, 6.4 Hz, 1H, rha-H5), 3.78 (dd, J = 9.6, 3.4 Hz, 1H, rha-H3), 3.68 (dd, J = 10.0, 3.2 Hz, 1H, glc-H2), 3.48 (m, 1H, agl-H3), 2.11 (s, 3H), 2.09 (s, 3H), 2.08 (s, 3H), 2.03 (s, 3H), 1.99 (s, 3H), 1.16 (d, J = 6.4 Hz, 3H, rha-H6), 0.90 (d, J = 6.4 Hz, 3H, agl-H21), 0.87 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.86 (d, J = 6.8 Hz, 3H, agl-H26 or H27), 0.82 (s, 3H, agl-H18 or H19), 0.66 (s, 3H, agl-H18 or H19). 13C-NMR (101 MHz, CDCl3) δ: 170.8 (s), 170.5 (s), 170.5 (s), 170.0 (s), 169.8 (s), 137.9 (s), 128.4 (d, 2C), 127.8 (d, 2C), 127.8 (d), 99.6 (d), 96.8 (d), 79.0 (d), 77.3 (d), 74.3 (d), 72.2 (d), 71.8 (d), 71.5 (t), 68.8 (d), 68.6 (d), 67.4 (d), 67.2 (d), 62.2 (t), 56.5 (d), 56.4 (d), 54.4 (d), 45.1 (d), 42.7 (s), 40.1 (t), 40.0 (t), 39.6 (t), 36.2 (t), 36.2 (t), 35.9 (d), 35.6 (s), 35.6 (d), 32.1 (t), 29.8 (t), 28.3 (t), 28.1 (d), 28.0 (t), 24.3 (t), 23.9 (t), 22.9 (q), 22.6 (q), 21.3 (t), 21.1 (q), 21.0 (q), 20.8 (q), 20.8 (q), 20.8 (q), 18.8 (q), 17.5 (q), 12.4 (q), 12.2 (q). HRMS m/z [M + Na]+ Calcd for C56H84O15Na 1019.5708. Found 1019.5689. Data for 36d-β: [α]D23 +9.6 (c 0.21, CHCl3). IR (ATR) 2926, 2853, 1742, 1466, 1456, 1443, 1366, 1237, 1168, 1116, 1078, 1058, 1041, 947, 903 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.34–7.25 (m, 5H), 5.23 (dd, J = 9.6, 9.6 Hz, 1H, glc-H3), 5.10 (dd, J = 3.2, 1.8 Hz, 1H, rha-H2), 5.04 (dd, J = 9.9, 9.9 Hz, 1H, rha-H4), 4.96 (dd, J = 10.0, 9.6 Hz, 1H, glc-H4), 4.95 (d, J = 1.8 Hz, 1H, rha-H1), 4.61 (d, J = 12.1 Hz, 1H), 4.51 (d, J = 7.8 Hz, 1H, glc-H1), 4.40 (d, J = 12.1 Hz, 1H), 4.29 (dq, J = 9.9, 6.4 Hz, 1H, rha-H5), 4.27 (dd, J = 12.4, 5.0 Hz, 1H, glc-H6), 4.08 (dd, J = 12.4, 2.3 Hz, 1H, glc-H6), 3.75 (dd, J = 9.9, 3.2 Hz, 1H, rha-H3), 3.70 (dd, J = 9.6, 7.8 Hz, 1H, glc-H2), 3.69–3.59 (m, 2H, glc-H5, agl-H3), 2.11 (s, 3H), 2.07 (s, 6H), 2.01 (s, 3H), 1.99 (s, 3H), 1.15 (d, J = 6.4 Hz, 3H, rha-H6), 0.90 (d, J = 6.4 Hz, 3H, agl-H21), 0.87 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.86 (d, J = 6.6 Hz, 3H, agl-H26 or H27), 0.77 (s, 3H, agl-H18 or H19), 0.65 (s, 3H, agl-H18 or H19). 13C-NMR (101 MHz, CDCl3) δ: 170.7 (s), 170.4 (s), 170.4 (s), 169.6 (s), 169.4 (s), 137.9 (s), 128.3 (d, 2C), 127.7 (d), 127.6 (d, 2C), 99.1 (d), 97.6 (d), 78.4 (d), 77.2 (d), 75.0 (d), 74.2 (d), 72.5 (d), 71.6 (d), 71.2 (t), 68.81 (d), 68.75 (d), 66.5 (d), 62.2 (t), 56.5 (d), 56.3 (d), 54.3 (d), 44.5 (d), 42.6 (s), 40.0 (t), 39.5 (t), 36.9 (t), 36.2 (t), 35.8 (d), 35.6 (s), 35.5 (d), 33.9 (t), 32.0 (t), 29.2 (t), 29.0 (t), 28.2 (t), 28.0 (d), 24.2 (t), 23.8 (t), 22.8 (q), 22.5 (q), 21.2 (t), 21.0 (q), 21.0 (q), 20.8 (q), 20.7 (q), 20.6 (q), 18.7 (q), 17.2 (q), 12.1 (q), 12.1 (q). HRMS m/z [M + Na]+ Calcd for C56H84O15Na 1019.5708. Found 1019.5691.

Cholestanyl 3,4,6-Tri-O-Ac-2-O-(3,4-di-O-Ac-2-O-Bn-α-L-rhamnopyranosyl)-β-D-glucopyranoside (36e)

In a reaction similar to that described for the synthesis of 36a, the use of 35e (55.5 mg, 40.9 µmol), TBAF (1.0 M solution in THF, 0.8 mL, 0.8 mmol), THF (0.4 mL), pyridine (0.4 mL), Ac2O (9.1 mg, 89 µmol), and DMAP (9.9 mg, 82 µmol) provided a crude product containing 36e. The reaction time and temperature were 3 h and reflux temperature of THF for the first step, and 1.5 h and 80 °C for the second step, respectively. The crude product was purified by CC (SiO2 2 g, hexane/EtOAc = 10/1 to 2/1) to give 36e (44.9 mg, 100% yield) as a colorless syrup. Data for 36e: [α]D23 −5.39 (c 2.25, CHCl3). IR (ATR) 3019, 2868, 1746, 1456, 1366, 1224, 1173, 1139, 1104, 1037, 917, 753 cm−1. 1H-NMR (400 MHz, CDCl3) δ: 7.35–7.26 (m, 5H), 5.20 (dd, J = 9.6, 9.2 Hz, 1H, glc-H3), 5.16 (dd, J = 10.0, 9.2 Hz, 1H, rha-H4), 5.12 (dd, J = 10.0, 3.2 Hz, 1H, rha-H3), 4.97 (dd, J = 9.6, 9.6 Hz, 1H, glc-H4), 4.96 (d, J = 1.6 Hz, 1H, rha-H1), 4.60 (d, J = 12.0 Hz, 1H), 4.55 (d, J = 8.0 Hz, 1H, glc-H1), 4.53 (d, J = 12.0 Hz, 1H), 4.35 (dq, J = 9.2, 6.4 Hz, 1H, rha-H5), 4.28 (dd, J = 12.4, 4.8 Hz, 1H, glc-H6), 4.08 (dd, J = 12.4, 3.6 Hz, 1H, glc-H6), 3.76 (dd, J = 9.2, 8.0 Hz, 1H, glc-H2), 3.74 (dd, J = 3.2, 1.6 Hz, 1H, rha-H2), 3.70–3.63 (m, 2H, glc-H5 and agl-H3), 2.09 (s, 3H), 2.01 (s, 3H), 2.00 (s, 3H), 1.96 (s, 3H), 1.94 (s, 3H), 1.18 (d, J = 6.4 Hz, 3H, rha-H6), 0.90 (d, J = 6.4 Hz, 3H, agl-H21), 0.86 (d, J = 6.8 Hz, 3H, agl-H26 or H27), 0.86 (d, J = 6.4 Hz, 3H, agl-H26 or H27), 0.80 (s, 3H, agl-H18 or H19), 0.64 (s, 3H, agl-H18 or H19). 13C-NMR (101 MHz, CDCl3) δ: 170.8 (s), 170.2 (s), 170.0 (s, 2C), 169.8 (s), 137.7 (s), 128.6 (d, 2C), 128.1 (d), 128.0 (d, 2C), 99.6 (d), 97.7 (d), 79.0 (d), 75.8 (d), 75.7 (d), 74.2 (d), 73.4 (t), 71.7 (d), 71.6 (d), 71.2 (d), 68.9 (d), 66.7 (d), 62.3 (t), 56.6 (d), 56.4 (d), 54.5 (d), 44.8 (d), 42.7 (s), 40.1 (t), 39.6 (t), 37.1 (d), 36.3 (s), 35.9 (d), 35.7 (t), 35.6 (t), 34.2 (t), 32.2 (t), 29.5 (t), 28.9 (t), 28.4 (t), 28.1 (d), 24.3 (t), 24.0 (t), 22.9 (q), 22.7 (q), 21.4 (t), 21.0 (q, 2C), 20.9 (q), 20. 9 (q), 20.8 (q), 18.8 (q), 17.2 (q), 12.4 (q), 12.2 (q). HRMS m/z [M + Na]+ Calcd for C56H84O15Na 1019.5708. Found 1019.5707.

Acknowledgments

The Ministry of Education, Culture, Sports, Science and Technology in Japan supported the program for the Strategic Research Foundation at Private Universities (S1311046), JSPS KAKENHI (15K13650), and mutual aid corporation-supported science research promotion fund partly supported this work.

Conflict of Interest

The authors declare no conflict of interest.

Supplementary Materials

The online version of this article contains supplementary materials.

Notes

This paper is dedicated to the memory of Prof. Dr. Hidetoshi Yamada, deceased on November 23, 2019.

References
 
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