Experimental and Computational Studies on Cp*^CyRh(III)/KOPiv-Catalyzed Intramolecular Dehydrogenative Cross-Couplings for Building Eight-Membered Sultam/Lactam Frameworks

Described herein is an unusual Cp^*CyRh­(III)-catalyzed intramolecular site-specific aryl C–H annulation, a highly chemoselective protocol providing direct access to eight-membered sultams/lactams with broad substrate/functional group tolerance. Experimental and computational studies reveal that such a transformation involves a unique PivOH-assisted aryl C–H activation/alkene insertion/β-H elimination/hydrogen-transfer process involving the Rh­(III)–hydride species as the active intermediate with the concomitant release of H₂ as the major byproduct, thus enabling the developed Cp^*CyRh­(III) catalysis with redox-neutral and highly atom-economical features.