Catalytic enantioselective Hosomi-Sakurai reaction of -ketoesters promoted by chiral copper(ii) complexes

A catalytic enantioselective Hosomi-Sakurai reaction of -ketoesters has been developed. A copper(ii) complex with a chiral bis(oxazoline) ligand bearing methanesulfonamide groups shows excellent catalytic activity to give ,-disubstituted -hydroxyesters in high yields with high enantioselectivities. This is the first successful method for the catalytic enantioselective 1,2-addition of -ketoesters with allylic silanes.