The synthesis of (+)-omphadiol and (+)-pyxidatol C was achieved through two independent strategies. For the synthesis of (+)-omphadiol, dicyclopentadienone was used as the workbench on which the three contiguous stereocenters of the cyclopentane could be introduced selectively. These include a tertiary alcohol and a selective protonation of an enolate. A ring-closing metathesis and a cyclopropanation
according to their biosynthetic similarities with the other compounds. The successful assignment of some Cotton effects was achieved by utilizing DFT calculations using simple model compounds. The plausible biosynthesis of 1–7 was also discussed on the basis of the structural commonality and general cyclohumulanoid biosynthesis. Compounds 2a and 5 were found to simultaneously induce hyphal swelling