Development of Chiral Catalysts by Asymmetric Activation for Highly Enantioselective Diethylzinc Addition to Imines

Based on the asymmetric activation concept, a library of chiral zinc complexes in situ formed by the combination of diimines derived from chiral 1,2-diphenyl-ethanene-1,2-diamine, BINOL derivatives, and diethylzinc are evaluated in the asymmetric addition of diethylzinc to N-acylimines. In the presence of 10 mol% L3ZnA1, high enantioselectivities and yields were provided for a wide range of aromatic imines in 1,2-dichloroethane at -25 °C.