Water-soluble chiral aminosulfonamides as ligands for ruthenium(II)-catalyzed asymmetric transfer hydrogenation

New water-soluble chiral aminosulfonamides were synthesized from (R,R)-1,2-diphenylethylenediamine. The ruthenium catalysts prepared from chiral aminosulfonamide ligands with [RuCl2(p-cymene)]2 were used in the asymmetric transfer hydrogenation of prochiral ketones in water with excellent conversion rates and enantioselectivities without adding any surfactants. The catalysts could be easily recovered and reused several times without loss of enantioselectivity and activity.