Modular amino acids and β-amino alcohol-based chiral ligands for enantioselective addition of diethylzinc to aromatic aldehydes

摘要

Enantioselective addition of diethylzinc to a series of aromatic aldehydes was developed using a modular amino acids and β-amino alcohol-based chiral ligand (2R)-N-[(1R,2S)-1-hydroxy-1-phenylpropan-2-yl]-3-phenyl-2-(tosylamino) propanamide (1f) without using titanium complex. The catalytic system employing 15 mol% of 1 f was found to promote the addition of diethylzinc (ZnEt2) to a wide range of aromatic aldehydes with electron-donating and electron-withdrawing substituents, giving up to 97% ee of the corresponding secondary alcohol under mild conditions.