Highly efficient asymmetric hydrogenation of alpha,beta-unsaturated carboxylic acids catalyzed by ruthenium(II)-dipyridylphosphine complexes

摘要

Two types of catalysts [RuL(benzene)Cl]Cl and Ru(OCOCH3)(2)L with the dipyridylphosphine ligands P-Phos and Xyl-P-Phos were applied in the asymmetric hydrogenation of alpha,beta-unsaturated carboxylic acids. The cationic complexes [RuL(benzene)Cl]Cl were found to be superior to the corresponding neutral complex Ru(OCOCH3)(2)L in this type of reactions. The catalysts exhibited excellent activities and enantioselectivities (up to 97% ee) in the asymmetric hydrogenation.