Enantioselective synthesis of binaphthol derivatives by oxidative couplingof naphthol derivatives catalyzed by chiral diamine copper complexes

A highly efficient process of aerobic oxidative coupling of 2-naphthol deri vatives catalyzed by 1 mol % of Cu(OH)Cl.TMEDA has been developed, Enantios elective oxidative coupling of naphthols was achieved by the use of 10 mol % of chiral catalysts prepared from proline-derived diamines and cuprous ch loride, affording the corresponding binaphthols in good enantioselectivitie s of up to 78% ee. The ester moiety at the 3-position of the substrate was found to be essential for the good asymmetric induction observed in the pre sent coupling reaction.