Silylene transfer to carbonyl compounds and subsequent Ireland-Claisen rearrangements to control formation of quaternary carbon stereocenters.

In this communication, we demonstrate that silylene transfer to carbonyl compounds provides a new method for regio- and stereoselective enolate formation. Silylene transfer to a range of alpha,beta-unsaturated esters under silver-catalyzed conditions proved to be a general method for the formation of oxasilacyclopentenes containing a cyclic silyl ketene acetal functionality. These oxasilacyclopentenes are useful synthetic intermediates that can undergo facile and selective Ireland-Claisen rearrangements and aldol addition reactions to provide products with multiple contiguous stereocenters and quaternary carbon centers.