Stereoconvergent Approach to the Enantioselective Construction of α-Quaternary Alcohols by Radical Epoxide Allylation.

Abstract

We describe a highly stereoconvergent radical epoxide allylation towards diastereomerically and enantiomerically enriched α-quaternary alcohols in two steps from olefins. Our approach combines the stereospecifity and enantioselectivity of the Shi epoxidation with the unprecedented Ti(III)-promoted intramolecular radical group transfer allylation of epoxides. A directional isomerization step via configurationally labile radical intermediates enables the selective preparation of all carbon quaternary stereocenters in a unique fashion.