作者:Hiroshi Hikino、Yasuko Hikino、Yasuyoshi Takeshita、Kanji Meguro、Tsunematsu Takemoto
DOI:10.1248/cpb.13.1408
日期:——
The structure and absolute configuration of valeranone have been established as V from the following evidence. Valeranone (V) was converted into IX via VIII (R=O, X=H), and β-eudesmol (X ; R=CH2) into XVI via XV (X=H). VIII (R=O, X=H) was shown to be a diastereomer of XV (X=H), and IX the enantiomer of XVI, thus establishing the absolute configuration of the C-10 methyl as α and that of the C-7 isopropyl group as β. The absolute configuration of the C-5 methyl was confirmed to be α by observing a negative Cotton effect of XXI, the difference of the nuclear magnetic resonance signals of the C-5 methyl of V and XXIV, and the conversion of XXII into XXIII. The absolute stereochemistry was also supported by the nuclear magnetic resonance spectra of XXVI (R=H and Ac) which revealed that the C-4 hydroxyl of R-configuration was located in a 1, 3-diaxial relation to the C-10 methyl group.
根据以下证据将戊酮的结构和绝对构型确定为V。戊酮(V)经由VIII(R=O,X=H)转化为IX,且β-桉醇(X;R=CH 2 )经由XV(X=H)转化为XVI。 VIII (R=O,X=H)显示为XV (X=H)的非对映异构体,IX为XVI的对映异构体,从而建立了C-10甲基的绝对构型为α,C-10甲基的绝对构型为α 7个异丙基为β。通过观察XXI的负Cotton效应、V和XXIV的C-5甲基的核磁共振信号的差异以及XXII向XXIII的转化,确认C-5甲基的绝对构型为α。绝对立体化学也得到XXVI的核磁共振谱(R=H和Ac)的支持,其揭示R-构型的C-4羟基与C-10甲基处于1, 3-二轴关系。