Ring Expansions of Oxetanes

Oxetanes are a class of important small heterocycles and intermediates in organic synthesis and have been widely applied in organic, pharmaceutical and polymer chemistries. As small heterocycles with a large ring tension, oxetanes not only prefer ring-opening reactions, but also favor ring expansions, to construct oxygen-containing common to large heterocyclic compounds. The ring expansion reactions of oxetanes, including the ring expansions with diazo compounds as carbene precursors, the metal catalyzed intermolecular cycloadditions and the intramolecular cycloadditions involving neighboring group participation, the nucleophilic ring expansion and so on are reviewed. Some reaction mechanisms of ring expansion reactions are analyzed, and new prospects for the future development of the ring expansion reactions are put forward.

Automated summary

Oxetanes are important small heterocycles widely used in organic, pharmaceutical, and polymer chemistry, with a preference for ring-opening and ring expansion reactions to construct various oxygen-containing large heterocyclic compounds. This review discusses the different ring expansion reactions of oxetanes and their reaction mechanisms, while also proposing new prospects for future development.