Synthesis of a Chiral Tridentate Ligand from Proline and Its Application to Enantioselective Addition of Diethylzinc to Aldehydes

Abstract A new chiral tridentate ligand [1‐(1‐methyl‐ S ‐pyrrolidin‐2‐ylmethyl)‐ S ‐pyrrolidin‐2‐yl]‐diphenylmethanol ( 1 ) has been successfully synthesized from S ‐proline. The structure of the ligand was characterized by NMR spectra and X‐ray diffraction analysis. Its catalytic ability has also been examined in enantioselective addition of diethylzinc towards aldehydes with 15%–84% enantiomeric excesses ( ee ).