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.