A general and efficient Lewis acid catalysed Mukaiyama-aldol reaction of difluoroenoxysilanes and ketones

We report a general and highly efficient Mukaiyama-aldol reaction of ketones and difluoroenoxysilanes. While the reaction of aryl ketones worked efficiently in the presence of Bi(OTf)(3), that of aliphatic ketones required the use of Sc(OTf)(3). In addition, Sc(OTf)(3) was capable of achieving excellent 1,2-selectivity in the corresponding reaction of alpha,beta-unsaturated ketones. This method provides a facile access to differently substituted beta-hydroxy alpha,alpha-difluoro ketones, versatile synthons for difluomethylated tertiary alcohols. (C) 2017 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.