Tertiary Phosphine Diversification via Photochemical P−C Chemoselective Cleavage of Phosphonium Salts

Differentially substituted phosphines are indispensable in medicines, materials, and catalysis, yet their customizable synthesis, traditionally depending on unstable P─H/halogen reagents, remains formidably challenging. Here, we report a photoredox strategy enabling controllable aryl substitution through chemoselective P─C cleavage. By engineering electron donor-acceptor complexes between phosphonium salts and tertiary amines, this metal-free protocol realizes three consecutive hydrocarbyl exchanges for delivering tri-diverse-aryl phosphines with transition metal contamination elimination and broad functional group tolerance including unprotected amines and hydroxyls, facilitating late-stage modification of drugs/commercial ligands and construction of P,O,S-tridentate architectures and chiral P-stereogenic centers. Mechanistic studies reveal the dynamic pentacoordinated-phosphorane-complex formation nature and the radical-intermediate pathway, while the chemoselectivity originates from different P─C bond strengths. This work establishes a modular and sustainable platform for programming-level precision phosphine engineering.