Dearomative Cyclization/Spirocyclization via Electrochemical Reductive Hydroarylation of Nonactivated Arenes

An electrochemical cyclization/spirocyclization hydroarylation via reductive dearomatization of a series of nonactivated arenes including N-substituted indoles, indole-3-carboxamide derivatives, and iodo-substituted benzamides is described. This protocol boasts high atom efficiency, broad substrate applicability, and excellent selectivity. Utilizing a simple undivided cell, various nonactivated arenes undergo cyclization/spirocyclization through the intramolecular addition of aryl radicals to an aromatic ring, yielding 50 indolines, spirocyclizative hydroarylation products, and phenanthridinones.