Journal of Synthetic Organic Chemistry, Japan
Online ISSN : 1883-6526
Print ISSN : 0037-9980
ISSN-L : 0037-9980
Volume 53, Issue 7
Displaying 1-9 of 9 articles from this issue
  • Haruhisa SHIRAHAMA
    1995 Volume 53 Issue 7 Pages 566-580
    Published: July 01, 1995
    Released on J-STAGE: November 16, 2009
    JOURNAL FREE ACCESS
    Starting from isolation and structural determination of mushroom poisons, various chemistry was developed.
    1. Isolation, structural determination and synthesis of a cyclohumulanoid, illudin, occurred in Lampteromyces japonicus were performed. Various cyclohumulanoids were chemically derived from humulene modeling after their biosynthesis. The entirely different mode of biosynthetical cyclization of humulene was chemically simulated employing mercuric salts and its reaction mechanism was disclosed. And this condition was used for the biosynthetic like synthesis of prostaglandin E1. Two cyclohumulanoids carrying a shifted methyl group were derived through a newly found “apparent 1, 2-shift” namely “cyclopropane sliding reaction”. The conformation of humulene was studied by molecular mechanics calculations and its four stable conformers were found. The conformational consideration improved biogenesis of cyclohumulanoid. The biosynthetical “conformationally selective cyclization” was chemically simulated. Application of molecular mechanics calculations to natural products was first developed and several findings were obtained.
    2. Isolation, structural determination and synthesis of a kainoid, acromelic acids, occurred in Clitocybe acromelalga were achieved. Because of extraordinary potent depolarizing activity, several analogs were synthesized through newly developed various effective routes. The relationship between biological activity and structure or conformation of substrate were studied using synthetic products. The role of the substituent at C4 of the kainoid was considered to transfer electrons to the receptor.
    3. Two cyclic polyether isolated from algae were totally synthesized. Of thyrsiferol, the construction of C-ring, a pyran carrying boat conformation, and A-ring, heavily substituted bromopyran, were key steps. Teurilene, a squalene derived meso-polyether with 8 chiral centers; was produced through a few steps using newly found mode of stereoselective oxidation of double bonds. Antivirus virantmycin was synthesized by stereoselective nitrene addition to an intramolecular double bond and its stereochemistry was determined. Grayanotoxin III, a heavily oxygenated four cyclic diterpene, was totally synthesized employing highly stereo-selective SmI2 induced radical coupling in the construction of three rings.
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  • Yasuo HATANAKA
    1995 Volume 53 Issue 7 Pages 581-592
    Published: July 01, 1995
    Released on J-STAGE: November 16, 2009
    JOURNAL FREE ACCESS
    Regio-and stereoselective cross-coupling reactions using allyltrifluorosilanes are reviewed. γ-Selective allylation of organic halides or triflates with allyltrifluorosilanes takes place in the presence of a fluoride salt and Pd (PPh3)4 as a catalyst, giving the corresponding allylic compounds in good yields. The regioselectivity of this reaction is strongly influenced by a palladium catalyst ; high α-selectivity was observed in reactions catalyzed by PdCl2 [Ph2P (CH2)nPPh2](n=2 or 3). Optically active allylsilanes undergo the γ-selective allylation of aryl triflates to give optically active allylic arenes. The absolute configuration of the allylic arenes could be controlled by choosing a fluoride salt. Allylation of quinones with allyltrifluorosilanes takes place with high regioselectivity in the presence of FeCl3·6H2O. This method was used to synthesize biologically active isoprenoid quinones such as plastoquinone-1 and vitamin K1.
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  • Hiroshi OHMIZU, Tameo IWASAKI
    1995 Volume 53 Issue 7 Pages 593-603
    Published: July 01, 1995
    Released on J-STAGE: November 16, 2009
    JOURNAL FREE ACCESS
    The comprehensive synthesis of a variety of lignans based on our conceptually new synthetic strategy is described.
    Lignans were synthesized effectively by using the key intermediate 2. The compound 2 was synthesized in a stereoselective manner by the Michael addition of the O-TBS cyanohydrin to 2-butenolide, followed by the aldol reaction of the resulting enolate with an aromatic aldehyde. The key intermediate 2 was converted into : lignans of the aryltetralin series including podophyllotoxin stereoselectively; 1-arylnaphthalene and 1-aryl-4-hydroxynaphthalene lignans in a one-pot procedure by the acid-catalyzed cyclization and the aromatizationlactonization, respectively; lignans of the furofuran and bislactone-type furofuran series by the stereoselective intramolecular cyclization. Finally, we describe the asymmetric synthesis of lignans utilizing the chiral benzyl-lactones 68 and 73 as key intermediates which were synthesized via the Michael addition of the cyanohydrin 15 to chiral α, β-unsaturated esters 65 and 71.
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  • Takashi TAKAHASHI, Masahiro MIYAZAWA, Makoto NAKAZAWA, Haruo YAMADA, K ...
    1995 Volume 53 Issue 7 Pages 604-619
    Published: July 01, 1995
    Released on J-STAGE: November 16, 2009
    JOURNAL FREE ACCESS
    Four synthetic approaches to the primary PGs and its Stork's intermediate, and two approaches to the carbacyclin and its isocarbacyclin analogue are presented. In the first approach, PGE2 was synthesized by the conjugate addition of vinylzincates to 2-cyclopentenones. In the second approach, the Stork's intermediate was synthesized by the [2, 3]-Wittig rearrangement. In the third approach, the 11-deoxy-Stork's intermediate was synthesized by the Pd(0)-catalyzed cyclization containing 1, 3-chirality transfer. In the fourth approach, PGE2 was synthesized by the enone-switching reaction of the β-alkoxy-α-methylene cyclopentanone. The carbacyclin and its isocarbacyclin skeleton were synthesized by the Claisen rearrangement and Diels-Alder reaction, respectively, and those stereoselectivities were examined based on MM 2 transition model.
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  • Shun-ichi HASHIMOTO, Takeshi HONDA, Yuki YANAGIYA, Makoto NAKAJIMA, Sh ...
    1995 Volume 53 Issue 7 Pages 620-632
    Published: July 01, 1995
    Released on J-STAGE: November 16, 2009
    JOURNAL FREE ACCESS
    The rational design and development of stereocontrolled glycosidation reactions has been the subject of intensive investigations. Our interest in this context has been centered on the design of the leaving groups of glycosyl donors coupled with their activation without resorting to precious, explosive, or toxic heavy-metal salts as promoters. In an effort to capitalize on the phosphorus-containing leaving groups, we have recently devised new glycosyl donors incorporating diphenyl phosphate, diphenylphosphinimidate, N, N, N', N'-tetramethylphosphoroamidate, phosphorodiamidimidothioate, or diethyl phosphite as leaving groups, the glycosidations of which constitute mild and efficient methods for the highly stereocontrolled construction of 1, 2-trans-β-and 1, 2-cis-α-glycosidic linkages. In this paper, several notable features of the present glyosidation methods coupled with the mechanistic aspects are described.
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  • Tsunehiko HIGUCHI
    1995 Volume 53 Issue 7 Pages 633-644
    Published: July 01, 1995
    Released on J-STAGE: November 16, 2009
    JOURNAL FREE ACCESS
    Heteroaromatic N-oxides were found to be excellent oxidants in the presence of ruthenium porphyrin. 2, 6-Disubstituted pyridine N-oxides plus a catalytic amount of Ru porphyrin oxidized olefins, sulfides, and ally or benzyl alcohols to afford epoxides, sulfoxides, and aldehydes, respectively, in high yields. These oxidations also proceeded using various heteroaromatic N-oxides, such as pyrazine N-oxides, as oxidants. Further, the oxidizing activity of this reaction system was greatly enhanced by the addition of acids such as hydrogen chloride or hydrogen bromide. The system in the presence of these acids effectively oxidized unactivated alkanes and aromatic compounds to give alcohols (or ketones) and p-quinones in high yields with high selectivity and an extremely high catalyst turnover number (up to 120, 000). This system offers practical advantages, such as mild conditions, tractability of oxidants and easy overall procedures.
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  • Nobue HAGIHARA
    1995 Volume 53 Issue 7 Pages 645-649
    Published: July 01, 1995
    Released on J-STAGE: November 16, 2009
    JOURNAL FREE ACCESS
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  • Toshiyuki HOSOI
    1995 Volume 53 Issue 7 Pages 650-651
    Published: July 01, 1995
    Released on J-STAGE: November 16, 2009
    JOURNAL FREE ACCESS
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1995 Volume 53 Issue 7 Pages 652
    Published: July 01, 1995
    Released on J-STAGE: November 16, 2009
    JOURNAL FREE ACCESS
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