Copper‐Mediated Tandem Thiolation and Cyclization Reaction: Facile Access to Thiochromones

A copper‐mediated intramolecular cyclization of o ‐bromoenaminone with elemental sulfur has been developed, providing efficient access to thiochromones. This transformation features a broad substrate scope, affording C2/C3‐unsubstituted thiochromones in moderate to excellent yields with good functional group tolerance. Furthermore, the established copper‐mediated protocol was applied to the late‐stage functionalization of bioactive molecules. Preliminary mechanistic studies suggest that the reaction proceeds via ortho thiolation with elemental sulfur followed by intramolecular cyclization.