Modular amino acids-based chiral ligands for copper-catalyzed enantioselective conjugation addition of diethylzinc to cyclic enones.

New amino acid-based modular chiral ligands were readily synthesized and used to catalyze the asymmetric conjugate addition of Et(2) Zn to various cyclic enones in the presence of a variety of copper sources. Moderately high ee of up to 72% were obtained using ligand (S)-1e under mild conditions.