Synthesis of (2H)-Indazoles through Rh(III)-Catalyzed Annulation Reaction of Azobenzenes with Sulfoxonium Ylides

The rhodium(III)-catalyzed C-H functionalization followed by intramolecular annulation reactions between azobenzenes and sulfoxonium ylides is described. This protocol leads to the efficient formation of 3-aryl (2H)-indazoles with a range of substrate scope. A high level of chemoselectivity and functional group tolerance of this transformation were also observed.