Chiral ligands for asymmetric synthesis: enantioselective addition of diethylzinc to aromatic aldehydes catalyzed by chiral N-α-pyridylmethyl amino alcohols

A series of chiral ligands 2a–d were conveniently prepared from β-amino alcohols through a two-step sequence and applied to catalysis of enantioselective addition of diethylzinc to benzaldehyde. Among them ligand 2c was found to show the best asymmetric induction for the reaction and catalyze the addition to various aromatic aldehydes to provide (R)-secondary alcohols in up to 98.3% ee.