Reactions of tris(trimethylsilyl) silanecarboxylates with organolithium reagents

Abstract

Chemical behavior of tris(trimethylsilyl)silamecarboxylates toward organolithium reagents was investigated. Treatment of triethylsilyl, triphenylsilyl, and methyl tris(trimethylsilyl)silanecarboxylate ( 1a-c) with organolithium reagents gave products which can be explained in terms of three types of reactions, the formation of lithium tris(trimethylsilyl)silanecarboxylate, abstraction of a trimethylsilyl group by the organolithium reagents, and addition of the organolithium reagents across the carbonyl bond. The formation of lithium tris(trimethylsilyl) silanecarboxylate was observed in the reactions of silyl carboxylates 1a and 1b, while addition of the organolithium to the carbonyl bond occurred in the reactions of 1b and 1e. Abstraction of a trimethylsilyl group was observed when tris(trimethylsilyl)silyllithium was used as the organolithium reagent. The reaction of 1b with dimethylphenylsilyllithium afforded dimethylphenylsilyl tris(trimethylsily)silyl ketone in good yield, but the bis(silyl) ketone thus formed readily underwent evolution of carbon monoxide even at −80°C. yielding (dimethylphenylsilyl)tris(trimethylsilyl)silane.