Salicifoline and salicinolide, new diterpene polyesters from Euphorbia salicifolia

Two new diterpenes (1 and 2) were isolated from a dichloromethane extract of fresh, whole plants of Euphorbia salicifolia: salicifoline (1) is the first representative of a new type of tricyclic diterpenes involving a novel 5-8-8 fused ring system, and salicinolide (2) is a bishomoditerpene lactone based on the jatrophane skeleton. The carbon skeleton of 1 is formally derived from jatrophane via transannular intramolecular CC bond formation between C-12 and C-17.