A Dual Cobalt‐Photoredox Catalytic Approach for Asymmetric Dearomatization of Indoles with Aryl Amides via C−H Activation

Abstract

AbstractIn this study, we unveil a novel method for the asymmetric dearomatization of indoles under cobalt/photoredox catalysis. By strategically activating C−H bonds of amides and subsequent migratory insertion of π‐bonds present in indole as reactive partner, we achieve syn‐selective tetrahydro‐5H‐indolo[2,3‐c]isoquinolin‐5‐one derivatives with excellent yields and enantiomeric excesses of up to >99 %. The developed method operates without a metal oxidant, relying solely on oxygen as the oxidant and employing an organic dye as a photocatalyst under irradiation. Control experiments and stoichiometric studies elucidate the reversible nature of the enantiodetermining C−H activation step, albeit not being rate‐determining. This study not only expands the horizon of cobalt‐catalyzed asymmetric C−H bond functionalization, but also showcases the potential synergy between cobalt and photoredox catalysis in enabling asymmetric synthesis of complex molecules.