Scalable Rhodium(III)‐Catalyzed Aryl C−H Phosphorylation Enabled by Anodic Oxidation Induced Reductive Elimination

Transition metal catalyzed C?H phosphorylation remains an unsolved challenge. Reported methods are generally limited in scope and require stoichiometric silver salts as oxidants. Reported here is an electrochemically driven Rh^III‐catalyzed aryl C?H phosphorylation reaction that proceeds through H₂ evolution, obviating the need for stoichiometric metal oxidants. The method is compatible with a variety of aryl C?H and P?H coupling partners and particularly useful for synthesizing triarylphosphine oxides from diarylphosphine oxides, which are often difficult coupling partners for transition metal catalyzed C?H phosphorylation reactions. Experimental results suggest that the mechanism responsible for the C?P bond formation involves an oxidation‐induced reductive elimination process.