Diels–Alder adducts from Celastraceae species

Celastraceae species are a rich source of adducts whose biosynthesis has been hypothesized as involving a diels–alder reaction. the co-occurrence of these natural terpenoids adducts with their corresponding precursors, and the reported regio- and stereoisomers support that their biosynthesis occur via a diels–alderase. triterpene dimers, composed of a quinonemethide and a phenolic nor-triterpene, are the most numerous group of adducts and are all restricted to the celastraceae family. this review covers natural diels–alder adducts from celastraceae species, providing an overview of the reported terpenoid adducts classified by their monomer nature. in addition, synthetic efforts on the chemical feasibility of the biosynthetic diels–alder reactions involved and the biological activities of these metabolites are discussed.