Kinetic Resolution of Racemic Ferrocenylphosphine Compounds by Enantioselective Oxidation Using Cyclic Selenoxides Having a Chiral Ligand

Cyclic selenoxides having an optically active binaphthyl skeleton work as the reagents for enantioselective oxidation of phosphines to the corresponding phosphine oxides. Treatment of a racemic 2-oxazolin-2-ylferrocenylphosphine with one of the selenoxides in carbon tetrachloride in the presence of phenol affords the corresponding phosphine oxide together with the unreacted starting phosphine, both with moderate enantioselectivities (the phosphine oxide, up to 13% ee; the phosphine, up to 29% ee).