General synthesis of novel chiral ruthenium catalysts and their use in asymmetric hydrogenation

Abstract

The first general synthesis of mononuclear hexacoordinate chiral ruthenium-complexes is presented. Four chiral ruthenium(II)(2-methylallyl)2 complexes containing Diop, Chiraphos, Norphos, and Binap were prepared in 50-71% yield under mild conditions, and were found to be effective for asymmetric hydrogenation of unsaturated carboxylic acids to give the corresponding saturated derivatives attaining 90% optical purity. © 1991.