Rhodium(I)‐Catalyzed P(III)‐Directed C–H Alkylation of Biarylphosphines With Maleimides

A Rh(I)‐catalyzed P(III)‐directed ortho ‐CH bond alkylation of biarylphosphines with maleimides is disclosed. The transformation extends phosphine‐directed CH bond alkylation to activated, substituted alkenes that introduce a stereogenic center during CC bond formation. A Rh(I)/acetate manifold enables efficient coupling of diverse N ‐alkyl and N ‐aryl maleimides with electronically varied biarylphosphines, including one exemple on gram scale. The products are obtained as mixtures of two diastereoisomers. Detailed 2D NMR studies, together with DFT calculations, show that the observed isomerism originates from the combination of the newly formed stereogenic center and restricted rotation about the biaryl C(aryl)–C(aryl) bond. Kinetic isotope effect and intermolecular competition experiments support a pathway involving phosphine‐directed CH bond activation, alkene insertion into a Rh–H intermediate, and reversible hydride transfer. Overall, maleimides emerge as competent partners for P(III)‐directed CH bond alkylation and provide access to amide‐functionalized phosphines with stereochemically rich conformational landscapes.