ASYMMETRIC HYDROGENATION OF PROCHIRAL CARBOXYLIC-ACIDS AND FUNCTIONALIZED CARBONYL-COMPOUNDS CATALYZED BY RUTHENIUM(II)-BINAP COMPLEXES WITH ARYL NITRILES (BINAP = (R)-S,2'-BIS(DIPHENYLPHOSPHINO)-1,1'-BINAPHTHYL OR (S)-2,2'-BIS(DIPHENYLPHOSPHINO)-1,1'-BINAPHTHYL)

Complexes RuCl2(ArCN)2(binap), II (binap = (R)- or (S)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl; ArCN = benzonitrile, a; 2-furancarbonitrile, b; pentafluorobenzonitrile, c) were prepared, and their solution properties were investigated by P-31 NMR measurements. The catalytic activities and enantioselectivities for IIa-c catalysed hydrogenation of some prochiral acids were very similar to those provided by Ru2Cl4(binap)2(NEt3), I. In the hydrogenation of beta-functionalized carbonyl compounds, however, IIa-c showed considerably lower activities and/or selectivities, compared with complex I. The differences in IIa-c catalysed reactions are discussed in relation to the coordinating abilities of ArCN in II.