New synthetic approaches for the construction of 2-aminophenoxazinone architectures

Elaborated molecular architectures, specifically those containing a 2-aminophenoxazinone scaffold, belong to one of the most ubiquitous and prominent classes of heterocyclic frameworks, going from natural products to biologically active pharmaceutical molecules and from agrochemicals to functional materials and polymers. Therefore, efficient synthetic strategies for the assembly of 2-aminophenoxazinone frameworks are always in demand and have gained attention in academic and industrial communities. Methodologies that involve cascade reactions generally catalyzed by transition metal complexes, such as iron, cobalt, manganese, copper, and zinc complexes, have stood out as a representative approach. Over the past few decades, a great deal of versatile, atom-economic, and straightforward protocols have been reported for the generation of value-added 2-aminophenoxazinone frameworks in a sustainable, powerful, and applicable manner. The state-of-the-art methodologies toward the construction of 2-aminophenoxazinone skeletons are summarized in this review, which could be divided into four categories: (1) construction of 2-aminophenoxazinone compounds catalyzed by transition metal complexes; (2) construction of 2-aminophenoxazinone compounds catalyzed by biosynthetic enzymes; (3) synthetic process routes of 2-aminophenoxazinone compounds; and (4) construction of 2-aminophenoxazinone compounds via other innovative methods.