Asymmetric hydrogenation of α,β-unsaturated sulfones by a rhodium/thiourea-bisphosphine complex

We herein report a method to synthesize chiral sulfone compounds. Catalyzed by a rhodium/ thioureabisphosphine complex, various alpha,beta-unsaturated sulfones were hydrogenated with high enantioselectivities. Kinetic studies suggested a first-order dependence of the reaction rate on the substrate concentration. Noticeable deactivation of the catalyst was observed in dichloromethane, which could be responsible for the eroded turnover number. The thiourea moiety was demonstrated to be important for high enantioselectivity and reactivity by control experiments.