Brønsted Base-Catalyzed Transformation of α,β-Epoxyketones Utilizing [1,2]-Phospha-Brook Rearrangement for the Synthesis of Allylic Alcohols Having a Tetrasubstituted Alkene Moiety.

Abstract

A stereoselective transformation of α,β-epoxyketones into alkenylphosphates having a hydroxymethyl group on the β-carbon was established by utilizing the [1,2]-phospha-Brook rearrangement under Brønsted base catalysis. The reaction involves the catalytic generation of an α-oxygenated carbanion located at the α-position of an epoxide moiety through the [1,2]-phospha-Brook rearrangement and the following epoxide opening. Further transformation of the alkenylphosphates by the palladium-catalyzed cross-coupling reaction with Grignard reagents provided allylic alcohols having a stereodefined all-carbon tetrasubstituted alkene moiety.