Rhenium‐Catalyzed Annulation Reactions

Transition‐metal‐catalyzed intra‐ and intermolecular annulation reactions have been widely investigated, owing to their important applications in the synthesis of natural products, pharmaceuticals, and functional materials. Rhenium lies at the interface of early and late transition metals in the Periodic Table, with its unique properties, such as low electronegativity and ability to activate C–H and C–C bonds, enabling a series of atom‐ and step‐economical annulation reactions from simple substrates. This Microreview aims to summarize the impressive progress in rhenium‐catalyzed annulation reactions in recent years from our own viewpoints and perspectives.