Visible‐Light‐Induced Cascade Cyclization to Heterocycles via Metal‐Free Semiconductor Photocatalysis

ABSTRACT Heterocyclic compounds constitute a fundamental class of molecular architectures ubiquitously in pharmacologically active substances and naturally occurring products, thereby attracting great attention. This study presents a metal‐free semiconductor photocatalysis system for the rapid access to various five‐to‐seven‐membered heterocyclic skeletons through a visible‐light‐induced radical cascade cyclization pathway. Valuable nitrogen‐, oxygen‐, and sulfur‐heterocycles, such as tetrahydroquinolines, chromanes, and thiochromanes, are obtained in high yields with operational simplicity without transition‐metal catalysis under mild reaction conditions. Moreover, gram‐scale workup and late‐stage functionalization of bioactive compounds highlight its practical potential in industrial chemical manufacture.