Regio- and Stereoselective Approach to 1,2-Di- and 1,1,2-Trisilylethenes by Cobalt-Mediated Reaction of Silyl-Substituted Dibromomethanes with Silylmethylmagnesium Reagents

摘要

Vinylsilanes are useful organometallic reagents in organic synthesis because the C(sp_2)-Si bonds undergo numerous transformations. Multiply silylated ethenes are thus likely to represent platforms for a variety of highly substituted ethenes. Moreover, multiply silylated ethenes themselves attract considerable attention from the viewpoint of structural organic chemistry. Despite their importance, there is a limited number of access routes to multiply silylated ethenes. Hydrosilylation of silylacetylenes and bissilylation of acetylenes are most convenient procedures. Scheme 1 (top) shows representative approaches, for instance, to trisilylethenes with three different silyl groups. However, difficulties are often encountered in such synthetic strategies in terms of regioselectivity and the occurrence of several side reactions.