A [(sec-allyloxy)dimesitylsilyl]stannane bearing a phenyl group on the olefin part reacts with n-BuLi in THF to give a cyclopropylsilane as a single diastereomer, in contrast to the [2,3]-sila-Wittig rearrangement affording an allylsilane, previously observed for a substrate bearing an alkyl group on the olefin part. The striking substituent effect is revealed by ab initio calculations in terms of the regioselectivity in the reaction of silyllithiums with an olefin.
烯烃部分带有一个苯基的[(仲烯丙基氧基)二甲基
硅烷基]
锡烷在
四氢呋喃中与正
叔丁基锂发生反应,生成单一非对映异构体的环丙基
硅烷,这与之前观察到的烯烃部分带有一个烷基的底物发生[2,3]-西拉-维蒂希重排反应生成烯丙基
硅烷的情况截然不同。根据
水苏鎓与烯烃反应的区域选择性进行的原子序数计算揭示了这种显著的取代基效应。