Pd/Co‐Catalyzed Asymmetric Hydrophosphinylation of Conjugated Enynes to Access Fully C(sp 2 )‐Substituted P(V) Center

Comprehensive Summary Phosphine oxides featuring P ‐stereogenic center are popularly used in chiral ligands, catalysts and materials. Related methods focus on the preparation of P(V) skeleton containing different types of carbon substituents for facile enantiocontrol. In comparison, phosphine oxide containing all three C(sp 2 )‐substituents is seldom studied. Here we describe a novel protocol to achieve fully C(sp 2 )‐substituted P(V) stereocenters via synergistic Pd/Co‐catalyzed hydrophosphinylation of conjugated enynes with masked P(V) nucleophile. 1,2‐Hydrophosphinylation is exclusively observed, different from prior work involving 1,4‐hydrophosphinylation. A group of newly modified chiral Boxmi ligands guarantee the high stereocontrol of the transformation. Mechanistic studies suggest the outer‐sphere allylic substitution as the rate‐determining step.