been studied, involving the location of the silicon atom on either olefinic carbon atom of the cyclisation precursor. In both cases 5-exo ring closure was the only cyclisation process observed. The stereoselectivity of these processes is discussed. These results contrast with related β-oxo ester cyclisations, in which competitive 7-endo mode is observed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
已开发出一种新的
钯催化烯丙基烷基化反应,可提供甲
硅烷基化 3-
乙烯基吡咯烷酮。该方法依赖于稳定的乙酰胺烯醇化物阴离子和含
硅的氮系 η3-烯丙基
钯部分之间的相互作用。已经研究了两种变体,涉及
硅原子在环化前体的任一烯烃碳原子上的位置。在这两种情况下,5-外环闭合是观察到的唯一环化过程。讨论了这些过程的立体选择性。这些结果与相关的 β-氧代酯环化形成对比,其中观察到竞争性 7-endo 模式。(© Wiley-
VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)