Seven-Membered Rings

New synthetic methods continue to be developed to construct seven-membered heterocyclic compounds containing one, two, or three of the heteroatoms N, O, or S. The focus of much of the literature has been on aromatic systems containing at least 1 N atom and has often been driven by a desire to prepare these heterocycles in a stereocontrolled fashion, the search for new bioactives, and the synthesis of natural products. Prominent synthetic methods include transition metal-catalyzed, cycloaddition/annulation, cascade-type, and CeH functionalization processes. Review articles on the synthesis of seven-membered nitrogen heterocycles through the Ugi multicomponent reaction (17CHE382), synthetic approaches, and biological activities of benzodiazepines (17MOC453), the isolation, structure determination, medicinal properties, and total synthesis of marine natural products containing an oxepanyl ring (17MAD361), the synthesis and medicinal importance of benzoxepines (17LDD1086), methods for the synthesis of 1,2,3-, 1,2,4-, 1,2,5-, and 1,3,5-triazepines (17JCCS1023), and the isolation, biosynthesis, and biological activity of natural products that contain a sevenmembered ring with three or more heteroatoms (17JNP3060), as well as indole-fused azepines and analogs as anticancer lead molecules (17EJM244) have been published.