The asymmetric conjugate addition of dialkylzincs is usually performed with Cu(OTf)2 in toluene. We show that by using a copper carboxylate in Et2O, THF, or EtOAc, we strongly improve the enantioselectivity with a given ligand. Ee values up to 99.1% could be reached with new ligands based on the induced atropisomerism of a simple biphenol unit. In addition, we show that the Lewis acid effect of Cu(OTf)2 is not a significant.