Chiral Lewis acid catalyzed resolution of racemic enol ester epoxides. Conversion of both enantiomers of an enol ester epoxide to the same enantiomer of acyloxy ketone

This paper describes an efficient kinetic resolution of racemic enol ester epoxides via a chiral Lewis acid catalyzed rearrangement. Both enantiomerically enriched enol ester epoxides and a-acyloxy ketones can be obtained through this resolution. A positive nonlinear effect is observed in this process. By taking advantage of the mechanistic duality in acid-catalyzed enol ester epoxide rearrangement, we can completely convert a racemic enol ester epoxide into an enantiomerically enriched a-acyloxy ketone by treatment with a catalytic amount of a chiral Lewis acid followed by a catalytic amount of an achiral protic acid.