Homogeneous and heterogeneous catalytic asymmetric reactions IV. Hydrogenation of the Ni complexes of cinnamic acid salts over MRNi catalyst

Substituted cinnamic acids containing a prochiral CC bond, and their LiI, KI, NiII and CaII salts, were prepared and their surface complexes on Ni were studied over a Raney-Ni catalyst modified with tartaric acid. The hydrogenation product of sodium cinnamate is optically active. Of the alkali metal salts of (E)-α-phenylcinnamic acid, the hydrogenation of the Na salt gives the highest optical yield (17%). The solvent used significantly influences the selectivity. The published data for the chiral RH complexes are listed for comparison with the results of the homogeneous and heterogeneous hydrogenations described.