Enantio- and diastereoselective boron conjugate addition to α-alkyl α,β-unsaturated esters

Abstract

We developed a copper-catalyzed enantio- and diastereoselective boron conjugate addition to α-alkyl α,β-unsaturated esters under base-free conditions. The approach showed excellent enantioselectivities (87–99% ee) and moderate to good conversions (51–99%), albeit with moderate diastereoselectivities (1 : 1–17 : 1 dr). The synthetic utility of this protocol was demonstrated.