Regioselective Synthesis of Benzo[b]phosphole Derivatives via Direct ortho-Alkenylation and Cyclization of Arylthiophosphinamides

A new regioselective synthetic methodology for benzo­[b]­phosphole derivatives has been developed. Thus, a range of functionalized benzo­[b]­phosphole oxides could be synthesized via Rh­(III)-catalyzed C–H alkenylation of arylthiophosphinamides with alkynes followed by formal phospha-Friedel–Crafts cyclization.