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.