NMR Spectra of Organogermanium Compounds. VI. NMR Spectra and Molecular Mechanics Calculations of 3-Methyl- and 3,3-Dimethylgermacyclohexanes
作者:Yoshito Takeuchi、Yasuko Ichikawa、Katsumi Tanaka、Norihiro Kakimoto
DOI:10.1246/bcsj.61.2875
日期:1988.8
Several 3-methyl- or 3,3-dimethylgermacyclohexanes were prepared and their 13C and 73Ge NMR spectra were determined. Steric energies for all of stereoisomers of some of these germacyclohexanes were calculated by MM2 program. The effect of axial 3-methyl group of germacyclohexanes upon its C-5 is much the same with the corresponding effect in cyclohexanes, and is much smaller than the effect caused by axial methyl on germanium upon C-3,5. A large upfield shift is recorded for germanium nuclei when there is an axial methyl on C-3 of germacyclohexanes.
制备了几种 3-甲基或 3,3-二甲基胚芽环己烷,并测定了它们的 13C 和 73Ge NMR 光谱。利用 MM2 程序计算了其中一些胚芽环己烷所有立体异构体的立体能。胚芽环己烷的轴向 3-甲基对其 C-5 的影响与环己烷中的相应影响基本相同,比锗的轴向甲基对 C-3,5 的影响要小得多。当锗环己烷的 C-3 上存在轴向甲基时,锗核会发生较大的上场偏移。