Asymmetric synthesis of oxygen- and nitrogen-substituted difluoromethylene products

Abstract

1,1-Difluoroalkyl sulfinylmethyl ketones 3 are synthetized in enantiomerically pure form through acylation of (+)-(R)-methyl p-tolyl sulfoxide (1) with α,β-difluorocarboxylates 2. These ketones have been reduced with complete diastereoselection to give the corresponding alcohols. Removal of the auxiliary sulfinyl group and further elaboration afforded enantiomerically pure 2-(benzyloxy)-3,3-difluoro alcohols, esters, oximes, hydroxylamines, and nitriles