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

ABSTRACT

We developed a copper-catalyzed enantio- and diastereoselective boron conjugate addition to α-alkyl α,ß-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.