Stereochemistry of a guaianolide from Cyathocline purpurea by high resolution NMR spectroscopy

Abstract The stereochemistry of a sesquiterpene, 6α-hydroxy-4(14),10(15)-guaianadien-8β,12-olide (2) was established by high resolution and 2D-NMR spectroscopy. Careful analysis of the long range couplings along with vicinal spin-spin coupling constants predict a trans fusion of the lactone ring. Further information on the stereochemistry of 2 was obtained from 2D-NOESY and ROESY experiments.