Enantiopure <i>P</i>‑Chiral Secondary\nPhosphines (P*HRR′) from the Catalytic Asymmetric Hydrogenation\nof PC Bonds

We\nreport the first bottleable enantiopure <i>P</i>-chiral\nsecondary phosphines from the rhodium-catalyzed asymmetric hydrogenation\nof phosphaalkenes. Catalytic asymmetric hydrogenation, a reaction\nof broad academic and industrial importance for CC, NC,\nand OC bonds, has not previously been reported for the PC\nbond. The hydrogenation of ArPCR<sub>2</sub> (Ar = Mes, <i>m</i>-Xyl and TMOP; R = Ph, 4-C<sub>6</sub>H<sub>4</sub>F) affords\nfour unprecedented <i>P</i>-stereogenic secondary phosphines\nin 76%–90% isolated yields with 91%–97% enantiomeric\nexcess (ee). These isolable <i>P</i>-chiral secondary phosphines\nare configurationally stable indefinitely in the solid state and show\nonly modest loss in ee when kept in solution for over a month at room\ntemperature.