Enantioselective Synthesis of 2-Hydroxyalkyl Diarylphosphinates by Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation

An asymmetric transfer hydrogenation of 2-oxo alkyl phosphinates in the presence of a chiral diamine ruthenium catalyst with HCOONa as a hydrogen source in aqueous 2,2,2-trifluoroethanol under mild conditions gave a wide range of chiral 2-hydroxyalkyl diarylphosphinates in enantiomeric excesses of 97-99% and in good yields. The absolute configuration of the products was determined to be R by single-crystal X-ray diffraction.