Intermolecular Antiselective and Enantioselective Reductive Coupling of Enones and Aromatic Aldehydes with Chiral Rh(Phebox) Catalysts.

The intermolecular reductive coupling reaction of cyclopent-2-enone and aromatic aldehydes was realized by chiral rhodium−(bisoxazolinyl)phenyl catalysts, Rh(Phebox-Ph)(OAc)2(H2O), with diphenymethylsilane as a hydride donor to give the corresponding β-hydroxyketones in high anti-selectivity (up to 96%) with high enantioselectivity (up to 93%).