Laevinoids A and B: Two Diterpenoids with an Unprecedented Backbone from Croton laevigatus

Chemical fractionation of the ethanolic extract of a Chinese herbal plant, Croton laevigatus, yielded laevinoids A (1) and B (2) with a new rearranged ent-clerodane scaffold named as laevinane. The structures of 1 and 2 were assigned on the basis of detailed spectroscopic analyses with their absolute configurations being established via single-crystal X-ray diffraction studies.