Indole Synthesis by Cobalt-Catalyzed Intramolecular Amidation via the Oxidatively Induced Reductive Elimination Pathway

C–H bond activation and functionalization using high-valent cobalt catalysis typically involves a Co(III)/Co(I) catalytic cycle. Because of the lack of evidence and challenges associated with the high reactivity and instability of Co(IV) intermediates, reports on the C–H functionalization mechanism investigation involving Co(IV) intermediacy are still underexplored. Herein, we report an efficient synthesis of indole-2-carboxylic esters via intramolecular amidation of α-amidoacrylates and experimental and computational studies of the reaction mechanism, which involves oxidatively induced reductive elimination from Co(IV) species.