OPTICALLY-ACTIVE COMPLEXES OF TRANSITION-METALS (RH(I), RU(II), CO(II) AND NI(II)) WITH 2-AMINOCARBONYLPYRROLIDINE LIGANDS - SELECTIVE CATALYSTS FOR HYDROGENATION OF PROCHIRAL OLEFINS

The synthesis and characterization of optically active complexes containing organic amides [-C(O)NHR] of the type [RhCl(COD)L], [RhCl(CO)2L], [RhCl(PPh3)2L], [RUCl2(COD)L], [RuCl,(PPh3)2L], [Co(acac)L]X and [Ni(acac)L]X, where L = (S)-2-t-butylaminocarbonylpyrrolidine or (S)-2-(3-triethoxysilyl)propylaminocarbonylpyrrolidine are reported. Their cationic species were prepared in the presence of a non-coordinating counterion (X = PF6- or ClO4-). The amino acid derivative is bi-dentate with N,N-coordination. The metal complexes with ligands containing the triethoxysilyl group, were anchored to silica and modified USY-zeolite. These complexes have been characterized by spectroscopic and analytical techniques. The complexes anchored to the zeolite, which contains profuse supermicropores, show a higher activity for alkene hydrogenation and produce a remarkable increase of enantioselectivity (> 95%) in the hydrogenation of ethyl (Z)-alpha-benzoylaminocinnamate, taken as a model, and they represent a truly heterogeneous counterpart of the homogeneous organometallic catalysts.