Recent Advances in the Electrochemical Functionalization of Indoles: Site‐Selective Strategies and Mechanistic Insights

Indoles, as aromatic heterocyclic alkaloids, are commonly found in natural products and pharmaceuticals and are valued as versatile building blocks in organic syntheses. Electrochemical methods have recently emerged as a sustainable and efficient strategy to regioselectively functionalize indoles at the C2, C3, N1, or multiple sites, utilizing electrons as traceless reagents. This review systematically categorizes recent advancements in electrochemical indole functionalization based on reaction sites, encompassing mono-, di-, and tri-functionalization and ring-opening reactions. A wide range of coupling partners have been exploited to construct CC, C-heteroatom, NC, and N-heteroatom bonds through cross-coupling, cyclization, difunctionalization, and dearomative difunctionalization reactions. The review discussed substrate scope, functional group tolerance, and reaction mechanisms, supported by illustrative schemes containing proposed mechanistic pathways, oxidation potentials, and potential bioactivities of the products, which aims to stimulate advancements in the regioselective functionalization of indoles.