Rhodium(III)-catalyzed Oxidative Coupling through C–H Bond Cleavage Directed by Phosphinoxy Groups

A straightforward synthesis of phosphaisocoumarins is achieved by the rhodium-catalyzed oxidative coupling of diarylphosphinic and phenylphosphonic acid derivatives with alkynes. The P–OH groups effectively act as the key function for the regioselective C–H bond cleavage. Related oxidative coupling of phenylphosphine oxides with alkenes can also be conducted smoothly under similar conditions.