Modern Methods for the Synthesis of 1,4‐Oxazepanes and their Benzo‐Derivatives

1,4-Oxazepanes are made up of a seven-membered ring containing one nitrogen and one oxygen atom in a 1,4-relationship. Some oxazepanes and their derivatives are already in clinical use, such as the tetracyclic antidepressants amoxapine and nitroxapine, as well as loxapine, which is used to treat schizophrenia. This chapter presents information that is organized according to the type of reaction used to form the seven-membered ring, and focuses on the key reaction and benzo-derivatives. It covers cyclization reactions, lactonization, hydroamination, cycloaddition, annulation reactions, reactions catalyzed by metals, and ring-expansion reactions, followed by examples of cascade and multicomponent reactions, and finally of synthesis using flow chemistry. The chapter also covers reactions in which there is head-to-tail ring-closure of the molecular chain; that is, reactions in which there is intramolecular formation of one new bond.