Table 4. Enantioselective Zinc–ProPhenol-Catalyzed Aldol Reaction of Glycine Schiff Bases with Ligand L6^a.

^aAll reactions were performed at rt for 24 h using 1 equiv of glycinate Schiff base and 2 equiv of aldehyde in toluene at c = 0.5 M, followed by a reductive treatment with NaBH₃CN (2.5 equiv) and AcOH (2 equiv) in MeOH at rt for 16 h. dr was determined by analysis of the ¹H NMR spectrum of the crude material.

^bYields are of the isolated pure syn diastereomer. Enantiomeric excesses were determined by HPLC with a chiral stationary phase.