Stereoselective total syntheses of uncommon sesquiterpenoids isolated from Jatropha neopauciflora.

The first total syntheses of two tricyclic sesquiterpenes 1 and 2, isolated from Jatropha neopauciflora, were completed from dimethyl D-tartrate in a stereoselective manner. The crucial steps in these syntheses involved not only the Rh(I)-catalyzed Pauson-Khand-type reaction of the allenene derivative leading to the exclusive formation of the bicyclo[4.3.0]nonenone framework possessing an angular methyl group but also a highly stereoselective construction of the isopropylcyclopropane ring.