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Volume 73, Issue 11
Displaying 1-10 of 10 articles from this issue
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Preface
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Yukishige Ito2015 Volume 73 Issue 11 Pages 1061
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESSDownload PDF (534K)
Accounts
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Shuichi Nakamura2015 Volume 73 Issue 11 Pages 1062-1071
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESSThe development of novel chiral catalysts is one of the most challenging areas in organic chemistry. This account summarizes our recent studies on chiral bis(imidazoline)-palladium pincer type catalysts (phebim-Pd). The catalysts can be used in the enantioselective reaction of a wide variety of nitrile compounds with imines giving products in high yields with good stereoselectivities. This process offers a simple and efficient route for the synthesis of functionalized β-aminonitriles and their derivatives. We also examine the enantioselective allylation of ketimines derived from isatins using chiral phebim-Pd complexes to afford products in high yields with good enantioselectivities.View full abstractDownload PDF (3369K) -
Hiromitsu Takayama2015 Volume 73 Issue 11 Pages 1072-1080
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESSOur recent efforts on the asymmetric total synthesis of three types of Lycopodium alkaloids, i.e., lycodine-type (lycodine and flabellidine), fawcettimine-type (huperzine Q, fawcettimine, and fawcettidine), and miscellaneous-type (lycoposerramine-R) alkaloids, are described, and the merits of biogenetic consideration in the chemical synthesis of natural products are emphasized.View full abstractDownload PDF (1370K) -
Daisuke Urabe, Hidenori Todoroki, Masayuki Inoue2015 Volume 73 Issue 11 Pages 1081-1091
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESS(−)-4-Hydroxyzinowol (1) is a potent inhibitor of P-glycoprotein, which has been implicated in multi-drug resistance in the treatment of cancer. The highly oxygenated structure of 1, comprising a trans-decalin AB-ring and a tetrahydrofuran C-ring, with six acyloxy groups and one hydroxy group has posed a formidable synthetic challenge. We achieved the total synthesis of this extremely complex structure in 36 steps from 5-acetoxynaphthalen-1-ol. Here our efforts to complete the total synthesis of 1 are described in detail.View full abstractDownload PDF (2167K) -
Makoto Iwata, Yuko Kamijoh, Kazuo Nagasawa2015 Volume 73 Issue 11 Pages 1092-1098
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESSPyrrole imidazole alkaloids (PIAs) are a huge, structurally diverse family of compounds that are biosynthetically derived from oroidin and its dimer or tetramer. Many PIAs show significant biological activities, including antitumor, immunosuppressive, and adrenoceptor-related activities. Because of the structural diversity and biological activities, there is considerable synthetic interest in PIAs. In this review, we describe our approaches to the synthesis of representative oroidin monomer-type PIAs, (+)-dibromophakellin (2), (+)-dibromophakellstatin (3) and (+)-cylindradine A (53).View full abstractDownload PDF (1170K) -
Fumitoshi Kakiuchi, Takuya Kochi2015 Volume 73 Issue 11 Pages 1099-1110
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESSCatalytic, regioselective C-H functionalizations have been extensively studied over the past two decades. In this account, we report our results on catalytic C-C, C-Si, and C-halogen bond formation reactions by substitution via the cleavage of C-H bonds. Catalytic arylation with arylboronates was developed and applied to the convenient synthesis of polycyclic aromatic hydrocarbons. Alkenylation reactions were also realized by the use of alkenylboronates and alkenyl esters. Various carbonyl-containing substituents were introduced using carbamoyl chlorides, alkyl chloroformates, acyl chlorides, and cyclic alkenyl carbonates. C-Si bonds were formed by reactions with hydrosilanes and vinylsilanes. C-H halogenation reactions were achieved by a combination of C-H bond cleavage and electrochemical oxidation and were applied to one-pot arylation reactions using the Suzuki-Miyaura coupling prodecure.View full abstractDownload PDF (1370K) -
Tatsuya Nabeshima, Masaki Yamamura, Gary J. Richards, Takashi Nakamura2015 Volume 73 Issue 11 Pages 1111-1119
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESSWe first describe N2O2-type dipyrrins, which behave as tridentate or tetradentate ligands for the preparation of main-group-element complexes including B, Al, Si, Ge, and Sn. Similar complexes were unstable or hard to prepare using usual bidentate dipyrrins. In particular, the stable hypercoordinate dipyrrin-silicon complexes showed interconvertible photo-optical properties. The Ge and Sn complexes were obtained in a similar way. Ar,O-BODIPYs were also synthesized from the N2O2-type dipyrrins. Their application to a light harvesting molecular assembly is also shown. Second, we demonstrate the usefulness and potential of dipyrrin complexes in supramolecular chemistry. The one-, two- and three-dimensional supramolecular architectures are available because multidentate dipyrrin derivatives can be easily obtained through chemical modifications of the dipyrrin skeleton. Last we describe the binding ability of the fluorine atoms in BODIPY to cationic guests to create a functional response to an external stimulus.View full abstractDownload PDF (1847K) -
Hidetoshi Tokuyama2015 Volume 73 Issue 11 Pages 1120-1129
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESSTotal syntheses of the biosynthetically-related monoterpene indole alkaloids, (−)-rhazinilam, (−)-rhazinicine, (−)-mersicarpine, leuconodine B, melodinine E, and leuconoxine are described. Total synthesis of (−)-rhazinilam was achieved by each of two strategies; 1) regioselective 1,3-dipolar cycloaddition of an optically active münchnone intermediate prepared from d-aspartic acid dimethyl ester; 2) construction of the indolizinone core by a gold-catalyzed double cyclization cascade. The second generation synthetic route was also applied to the first asymmetric total synthesis of (−)-rhazinicine. In addition, the intramolecular gold-catalyzed double cyclization cascade was extended to a novel synthesis of substituted pyrroles, in which gold catalysts behaved as an auto-tandem catalyst, and played a dual role in activating terminal acetylenes both by forming gold acetylides and by π-coordination. A concise total synthesis of (−)-mersicarpine was achieved by an six-pot/nine-step sequence in 21% overall yield from commercially available 2-ethylcyclohexanone. An azepino[3,2-b]indole intermediate was synthesized via d’Angelo’s asymmetric Michael addition, Fischer indole synthesis, and DIBALH-mediated reductive ring-expansion reaction. Finally, divergent total syntheses of leuconodine B, melodinine E, and leuconoxine were achieved. The crucial formation of the key [5.5.6.6]diazafenestrane intermediate was accomplished by oxidative cyclic aminal formation and regioselective ring-closing metathesis.View full abstractDownload PDF (1407K) -
Raghu Nath Dhital, Masahiro Ehara, Hidehiro Sakurai2015 Volume 73 Issue 11 Pages 1130-1140
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESSThe Palladium nanoclusters (NCs)-catalyzed carbon-carbon bond-forming reaction has emerged as a powerful tool in organic synthesis and has been intensively studied over the past few decades. Recently, a series of gold NC-catalyzed carbon-carbon bond formation has also been introduced even though contamination by PPB levels of palladium impurities has caused debate. Besides the development of gold and palladium NCs, new strategies for the design of gold-based bimetallic catalysts have subsequently been introduced. These burgeoning strategies are remarkable for achieving reaction under ambient conditions, with unique selectivity, and high activity. Among the various bimetallic NCs, Au/Pd has attracted a great deal of attention because of its superior catalytic activities in various types of reaction. In attempts to rationalize the synergistic effects observed with these catalysts, two major factors have been suggested, the ensemble effect and the ligand effect and these effects have been well documented in recently published reviews. This account provides an overview of recent developments in the use of gold-palladium bimetallic NCs for C-X bond activation. A specific objective is to demonstrate the effect of inclusion of Au as nearest heteroatom in the Au/Pd alloy in C-X bond activation from the viewpoint of both experimental observations and quantum chemical calculations.View full abstractDownload PDF (2917K) -
Michinori Suginome, Takeshi Yamamoto, Yuuya Nagata2015 Volume 73 Issue 11 Pages 1141-1155
Published: November 01, 2015
Released on J-STAGE: December 21, 2015
JOURNAL OPEN ACCESSStudies on the synthesis, helical structure, switchable screw-sense induction, catalytic function, and chiroptical properties of poly(quinoxaline-2,3-diyl)s since late 1980’s are described.View full abstractDownload PDF (4297K)
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