Photosensitizer-free synthesis of benzochalcogenophenes via photoinduced cascade cyclization

Abstract

We present an efficient and eco-friendly methodology for the preparation of 3-(arylsulfonyl)benzothiophenes under mild conditions, via a visible light-promoted radical addition/cyclization cascade sequence, conducted in the absence of any external photocatalyst, oxidant, or metal. Mechanistic studies indicate that the process likely involves a two-photon excitation pathway, which subsequently induces a single-electron transfer process to generate aryl sulfonyl radical intermediates.