Enantioselective Cu-catalyzed conjugate addition of diethylzinc to acyclic aliphatic enones.

[reaction: see text] A new P-chiral phosphine bis(sulfonamide) ligand has been developed that allows the Cu-catalyzed enantioselective conjugate addition of Et(2)Zn to acyclic aliphatic enones. The reactions proceed with excellent levels of enantioselectivity (90-95% ee) with a range of enone substrates, involve the use of only 1.2 equiv of Et(2)Zn, and give best results at ambient temperature.