Enantioselective addition of diethylzinc to aldehydes with novel chiral C2-symmetric dimeric ligands

Novel (S)-valinol-based chiral C2-2,2′-ethylenediiminodiethanol derivatives 4a and 4b have been synthesized and used as chiral catalysts in the enantioselective addition of diethylzinc to aldehydes. (R)-1-Phenylpropanol has been obtained in up to 91% enantiomeric excess.