Enantiopure P-Chiral Secondary Phosphines (P*HRR′) from the Catalytic Asymmetric Hydrogenation of P═C Bonds

Abstract

We report the first bottleable enantiopure P-chiral secondary phosphines from the rhodium-catalyzed asymmetric hydrogenation of phosphaalkenes. Catalytic asymmetric hydrogenation, a reaction of broad academic and industrial importance for C�C, N�C, and O�C bonds, has not previously been reported for the P�C bond. The hydrogenation of ArP�CR 2 (Ar = Mes, m-Xyl and TMOP; R = Ph, 4-C 6 H 4 F) affords four unprecedented P-stereogenic secondary phosphines in 76%−90% isolated yields with 91%−97% enantiomeric excess (ee). These isolable P-chiral secondary phosphines are configurationally stable indefinitely in the solid state and show only modest loss in ee when kept in solution for over a month at room temperature.