Conjugate addition of diethylzinc to alpha,beta-unsaturated lactones catalyzed by copper-phosphite complexes

Highly enantioselective conjugate addition of diethylzinc to alpha,beta-unsaturated lactones was achieved by using chiral diphosphite-copper catalysts; the structure of a chiral diphosphite-copper(I) catalyst was determined by single crystal X-ray diffraction.