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

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 1f 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.