Catalytic asymmetric hydrogenation using ruthenium(II) chiral phosphine complexes

Abstract
The ruthenium(II) complexes [Ru2X4{(+)(diop)}3][ X = Cl, Br; diop = 2,2-dimethyl-1,3-dioxolan-4,5-bis(methylene)bis(diphenylphosphine)], which contain a bridging bridentate phosphine ligand, catalyse under mild conditions the hydrogenation of unsaturated carboxylic acids and can give products of high optical yields (ca. 60%).