Crystal Structure of Cucubaldiol,a Novel Norsesquiterpenoid Incorporating a Bicyclo[2.2.2]octene Ring System from Cucubalus baccifer (Caryophyllaceae)

Cucubaldiol ( 1 ), a novel norsesquiterpenoid incorporating a bicyclo2.2.2]octene ring system, was isolated from the whole plants of Cucubalus baccifer L. Its structure was determined on the basis of spectroscopic data especially by 2D‐NMR and X‐ray diffraction analyses.