An Iterative Catalytic Route to Enantiopure Deoxypropionate Subunits:  Asymmetric Conjugate Addition of Grignard Reagents to α,β-Unsaturated Thioesters

Abstract

A highly enantioselective (up to 96% ee) conjugate addition of Grignard reagents, in particular, MeMgBr, to alpha,beta-unsaturated thioesters is provided as well as its application to a diastereo- and enantioselective iterative route to syn- and anti-1,3-dimethyl arrays and deoxypropionate subunits. The versatility of the method is illustrated in the synthesis of (-)-lardolure, a multimethyl-branched insect natural pheromone.