Radical-Mediated Tandem Cyclization to Construct Seven-Membered Nitrogen/Oxygen Heterocycles

Owing to the special chemical structure of the seven-membered heterocyclic skeleton and the unique chemical properties of the heteroatoms contained, it is widely used in natural products and drug molecules.However, the development of synthetic methodology for these structures is challenging due to the unique thermodynamic and kinetic characteristics of nitrogen/oxygen-containing seven-membered heterocyclic frameworks, as well as their own unique cross-ring forces.Therefore, it is of great significance to develop simple and efficient methods for the construction of seven-membered heterocyclic compounds.Compared with traditional synthetic methods, radical reactions can avoid the limitations of poor atom economy and harsh reaction conditions.In this review, the recent synthetic strategies for the construction of seven-membered nitrogen/oxygen-containing heterocyclic compounds using radical tandem cyclization reactions are summarized.