Highly enantioselective catalytic asymmetric hydrogenation of (beta)-keto esters in room temperature ionic liquids

Polar phosphonic acid-derived Ru-BINAP systems were used to catalyze asymmetric hydrogenation of (beta)-keto esters in room temperature ionic liquids (RTILs) with complete conversions and ee values higher than those obtained from homogeneous reactions in MeOH (up to 99.3%), and were recycled by simple extraction and used for four times without the loss of activity and enantioselectivity.