Mixed organofluorine-organosilicon chemistry. 13. One-pot synthesis of difluoroaldols from acylsilanes and trifluoromethyltrimethylsilane. Application to the synthesis of a difluoro analogue of egomaketone

Difluoroaldol compounds 3 were synthesized in a one-pot procedure involving an acylsilane 1, trifluoromethyltrimethylsilane (TFMTMS), and an aldehyde. The key intermediate of this reaction is a difluoroenoxysilane 2. Ytterbiu m triflate proved to be a very efficient catalyst for promoting the aldol t ype reaction under very mild conditions. The potential of this reaction for the convergent synthesis of difluorinated compounds was illustrated by the synthesis of difluoroegomaketone 7d through dehydration of the correspondi ng aldol compound 3d.