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Volume 48, Issue 1
Displaying 1-7 of 7 articles from this issue
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Eiji IMOTO1990 Volume 48 Issue 1 Pages 2-15
Published: January 01, 1990
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe concepts of electronegativity proposed by Iczkowski-Margrave, Hinze-Jafféand Klopman, and also the methods for calculation of group electronegativities presented by Huheey, Bratsch, Mullay, Inamoto-Masuda and Marriott et al. are explained. The data of atomic, orbital and group electronegativities are listed in appendixes.View full abstractDownload PDF (1563K) -
Kiyoshi TANAKA1990 Volume 48 Issue 1 Pages 16-28
Published: January 01, 1990
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThis review deals with the application of fluorine-containing heterocycles as biological active compounds and functional material. Various approaches to the four-, five-, and six-membered heterocycles and the relative compounds bearing fluorine atom or trifluoromethyl group are summarized and the synthetic methods are mainly depending on cyclization of the fluorinated building blocks.View full abstractDownload PDF (1302K) -
Hisashi TAKAHASHI, Toshiaki MORIMOTO, Kazuo ACHIWA1990 Volume 48 Issue 1 Pages 29-42
Published: January 01, 1990
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSRecently, we have proposed a new designing concept, “Respective Control Concept”, for developing highly efficient chiral bisphosphine ligands. On the basis of our concept, new chiral bisphosphine ligands, BCPM, MOD-BPPM, MOD-DIOP, etc. have been synthesized. Their rhodium complexes have been found to show very high catalytic activity and enantioselectivity in the asymmetric hydrogenations of prochiral carbonyl and olefinic compounds. Practical asymmetric syntheses of useful biologically active compounds have been realized by using these hydrogenations as key reactions.View full abstractDownload PDF (1824K) -
Toshio HONDA, Masayoshi TSUBUKI1990 Volume 48 Issue 1 Pages 43-55
Published: January 01, 1990
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSSteroids are one of the most interesting and the most widely distributed and also one of the most structurally complex families of naturally occurring substances. Due to their great importance for biology and medicine, intensive efforts have been devoted into their synthesis. Especially, stereoselective construction of steroidal side chains has been the subject of extensive synthetic efforts, because their physiological activity has been reflected in the stereochemistry of the side chain. This article describes the highly stereoselective construction of steroidal side chains, where furan and its analogues are employed as the carbon-unit sources of the side chains. Moreover the strategies developed above are applied to the synthesis of several natural products, such as brassinolide and ecdysone.View full abstractDownload PDF (1334K) -
Akira YOSHIOKA, Toshiro YAMADA1990 Volume 48 Issue 1 Pages 56-64
Published: January 01, 1990
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSAn economical synthetic process of methyl jasmonate has been established.
Total yield of this process is higher than 60 % for all five steps from cheaply available adipic acid. 2-Pentyny1-2-cyclopentenone, the key intermediate in this route, is synthesized by applying the improved palladiumcatalyzed enone formation from allyl β-keto carboxylate as a key reaction. The pentynyl moiety is introduced by the use of pentynyl chloride which is prepared in two steps from 2-butyne, our original source, cheaply.View full abstractDownload PDF (1229K) -
Properties and Reactivity of Excited StatesRyoichi NAKAGAKI1990 Volume 48 Issue 1 Pages 65-70
Published: January 01, 1990
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSPhotochemical reduction of nitroaromatic species has been critically reviewed. The photoreaction mechanism of nitroaromatic compounds has been less understood in comparison with that of aromatic carbonyl compounds, because the properties of nitroaromatic excited states are still ambiguously described. At least three different lower electronically excited states are involved in the longest wavelength absorption band. These are La (long-axis polarization), Lb (short-axis polarization), and nπ* states. The relative location of these three states is dependent upon the nature of substituents and solvents, and therefore the characterization of lower excited states of nitrobenzene derivatives are rather difficult.
Since complications due to the secondary process of primary photoproducts are inevitable, an intermolecular photoreduction for nitroaromatic species is practically of minor importance. On the other hand, some intramolecular photoredox reactions involving ο-nitrobenzyl moiety have been used for photosensitive protection of a certain functional group and photoresists.View full abstractDownload PDF (694K) -
d-Tartaric acidYoshikazu YAMAMOTO1990 Volume 48 Issue 1 Pages 71-72
Published: January 01, 1990
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (162K)
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