C-Glycosides to Fused Polycyclic Ethers. A Formal Synthesis of (±)-Hemibrevetoxin B

This paper describes a formal total synthesis of the marine ladder toxin hemibrevetoxin B from Danishefsky's dienes. This approach couples the generation of C-glycosides from cyclic enol ethers with metathesis or acid-mediated annulation reactions. The result is a highly efficient synthesis of the tetracyclic ring system of hemibrevetoxin B.