Mesoporous Silica Nanosphere Supported Ruthenium Catalysts for Asymmetric Hydrogenation

Chiral Ruthenium–diphosphine–diamine complexes with a siloxy pendant are grafted onto mesoporous silica nanospheres. The resulting supported ruthenium catalysts are highly active for the asymmetric hydrogenation of aromatic ketones to afford chiral secondary alcohols and racemic aryl aldehydes to give chiral primary alcohols (see scheme). This immobilization strategy should be amenable to the design of similar heterogeneous catalysts.