A Synthesis of the Carbocyclic Core of Maoecrystal V

An approach toward the synthesis of the complex polycyclic diterpene maoecrystal V (1) is described. Construction of the advanced tetracyclic core structure (i.e., 19) was achieved in 13 steps from 3,3-dimethylcyclohexanone (6) by employing a stereoselective Nazarov cyclization followed by a Diels-Alder reaction to forge the two contiguous quaternary stereocenters.