Oxidative <i>N</i>‑Arylation for Carbazole Synthesis by C–C Bond Activation

Activation of strong C–C σ-bonds is quite challenging. We report here an intramolecular oxidative <i>N</i>-arylation method of biarylsulfonamides via cleavage of C–C bonds toward synthesis of heterocycle carbazoles. The stability of generated carbocations could control the reactivity of a nitrenium ion for the C–N bond formations at the <i>ipso</i>-carbon via a retro-Friedel–Crafts-type reaction using hypervalent iodine­(III) reagent PhI­(OAc)<sub>2