Oxidative N-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 N-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 ipso-carbon via a retro-Friedel-Crafts-type reaction using hypervalent iodine(III) reagent PhI(OAc)2.