Volatile constituents of Clausena willdenovii: Structures of the furanoterpenes α-clausenan, diclausenan A and diclausenan B

Four furanoid terpenic compounds, α-clausenan, rosefuran (γ-clausenan) and diclausenans A and B, were isolated from the essential oil of the leaves of Clausena willdenovii. Their structures were determined by chemical and spectral data. The occurrence of a high concentration of rosefuran is noteworthy. Selenium dioxide oxidation of diclausenan gave an unusual product, identified as an epoxy-dicarbonyl compound.