Nickel-Catalyzed Electroreductive Heck Reaction: A Divergent Synthesis of C7- or C2-Arylindolines

Herein, we present a novel electrochemically driven nickel-catalyzed Heck reaction of readily available N-arylacrylindoles for the construction of both 7-arylindolines and 2-arylindolines. The reaction proceeds in an undivided electrochemical cell and employs a sacrificial zinc anode as the reductant. This catalytic protocol features a consecutive electroreductive process under exceedingly mild reaction conditions, with moderate yields. Detailed mechanistic studies indicate that the reaction involves a domino sequence of intramolecular electroreductive Heck arylation and selective C-C or C-O bond cleavage, which could be accomplished by aryl migration or carbethoxy removal.