A sesquiterpene dimer from Xylopia aromatica

Abstract

A new guaiane dimer has been isolated from the leaves of Xylopia aromatica. The natural product, whose IUPAC name is [11α,12β,13α,21β]-7-hydroxy-16-oxo-17-isopropylidene-1α,5,5,9β,14α,20-hexamethyl-6- oxaheptacyclo[10.9.1.02,10.04,7.012,21.013,19]docosa-2(10),3,19-triene, seems to have been formed by cycloaddition of two cyclopentadiene precursors, and contains an unusual hemiacetal oxetane ring. The structure was elucidated mainly by 1D and 2D NMR techniques; NOESY spectra were instrumental in the determination of stereochemistry.