| The development of a strategy for the synthesis of the eunicellin diterpene core is described. A diastereoselective glycolate alkylation, a ring-closing metathesis to construct the oxonene ring, an intramolecular Diels-Alder reaction to construct the oxatricyclic ring system of the eunicellins simultaneously installing four contiguous stereocenters at Cl, C10, C13 and C14, and a stepwise triacetate formation we be discussed. A highly selective synthesis of ophirin B is described. The synthesis of ophirin B constitutes the first total synthesis of a C13, C18 oxygenated eunicellin diterpene. Efforts toward the total synthesis of astrogorgin will be described. |
