Rearrangement and Cyclization of Enamine Thianthrenium Salts: Effective Access to Substituted Indoles.

A facile base-mediated cyclization and rearrangement of enamine thianthrenium salts for the construction of indole compounds is disclosed. In this reaction, sequential cleavage of two C-S bonds and subsequent formation of C-N and C-C bonds furnish a series of substituted indoles in moderate to good yields. Furthermore, an efficient late-stage functionalization of enamine compounds is established. The method features a wide substrate scope, good functional group tolerance, and low-cost starting materials.