Unusual D:B-friedobaccharane and oxygenated friedelane-type triterpenoids from Salvadorean Celastraceae species

► Unusual D:B-friedobaccharanes and friedelane-type triterpenes from Celastraceae species. ► Chemotaxonomic relevance of D:B-friedobaccharanes in Celastraceae species. ► Determination of absolute configuration by application of the Riguera ester procedure. ► Plausible biogenetic pathway for 2,3-seco-2,24-epoxy-3,24-olide-D:A-friedooleanane triterpenes.