Electrochemical Dearomatization of Indoles: Access to Diversified Functionalized Spirocyclic Indolines

Spirocyclic indolines are widely present in drug-like molecules and alkaloids, so the synthesis of functionalized spirocyclic indolines could provide a promising approach to enrich the drug candidate library, which is highly important in drug discovery. Radical-induced dearomatization of indole can offer a straightforward strategy to access the dearomatized skeleton, which has gained increased significance in the past decades. In contrast to conventional organic synthesis, electrosynthesis has become a green and sustainable strategy for the oxidation of indole nucleus and for the generation of radicals. This review will focus on the electrochemical dearomatization of indoles for the synthesis of diversified, functionalized 3,3-spirocyclic indolines over the past decade.