Organomagnesium Synthesis of sec-Butyl- and tert-Alkylchlorogermanes and Their Reaction with Ethynylmagnesium Bromide
作者:O. G. Yarosh、M. G. Voronkov、L. V. Zhilitskaya、N. O. Yarosh、A. I. Albanov、I. M. Korotaeva
DOI:10.1007/s11176-005-0305-z
日期:2005.5
The limits of application of organomagnesium synthesis to the substitution of chlorine atoms in tetrachlorogermane with bulky alkyl groups are established. The reaction of tetrachlorogermane with 2-butylmagnesium chloride leads to the substitution of one, two, or three chlorine atoms, yielding the corresponding alkylchlorogermanes (MeEtCH)nGeCl4-n . The reaction of GeCl4 with tert-alkylmagnesium halides leads to the substitution of only one chlorine atom, yielding tert-alkyltrichlorogermanes RMe2CGeCl3 (R = Me, Et, Bu). tert-Butyltrichlorogermane reacts with ethylmagnesium bromide to give ethyl(tert-butyl)dichlorogermane. Isopropyltrichlorogermane reacts with tert-butylmagnesium chloride to give isopropyl(tert-butyl)dichlorogermane. This shows that the organomagnesium synthesis does allow linking of two bulky substituents to the germanium atom. The reaction of tert-alkyltrichlorogermanes and 2-butyltrichlorogermane in THF with ethynylmagnesium bromide, in which the hydrocarbon group is the most sterically accessible, allows substitution of all the three chlorine atoms, yielding the corresponding alkyl(triethynyl)germanes. The latter compounds react with the Grignard reagent and trimethylchlorosilane to give the corresponding alkyl(trimethylsilylethynyl)germanes.
有机镁合成在用笨重的烷基取代四氯锗烷中氯原子的应用范围已被确立。四氯锗烷与2-丁基镁氯反应能够替代一个、两个或三个氯原子,生成相应的烷基氯锗烷(MeEtCH)nGeCl4-n。四氯锗(GeCl4)与叔烷基镁卤化物反应仅能替代一个氯原子,生成叔烷基三氯锗烷RMe2CGeCl3(R = Me,Et,Bu)。叔丁基三氯锗与溴化乙基镁反应生成乙基(叔丁基)二氯锗烷。异丙基三氯锗与叔丁基镁氯反应生成异丙基(叔丁基)二氯锗烷。这个结果表明,有机镁合成确实允许在锗原子上连接两个笨重的取代基。在THF中,叔烷基三氯锗与2-丁基三氯锗与乙炔基镁溴反应,其中碳氢基团是最易获得的空间位阻团,能够替代所有三个氯原子,生成相应的烷基(三乙炔基)锗烷。后者化合物与格里尼亚试剂和三甲基氯硅烷反应生成相应的烷基(三甲基硅乙炔基)锗烷。