Ketal-tethered intramolecular Diels-Alder cycloaddition to the 2-oxadecalin spiroketal core of antifungal agent Fusidilactone C

ORGN 187

Sunil K. Ghosh, ghosh@chem.umn.edu, Jiashi Wang, and Richard P. Hsung. Department of Chemistry, University of Minnesota-Twin Cities, 207 Pleasant Street, SE, Minneapolis, MN 55455
Fusidilactone C, a new polycyclic lactone, was isolated from the culture broth of fusidium sp. in 2002. Fusidilactone C possesses a structural complexity rivaling that of tetrodotoxin, thereby representing a unique challenge. It also comprises a rare oxoadamantane structural motif and, in addition to its spiroketal, also has an unusual ether-bridged hemiacetal held in place by the rigid frame of oxoadamantane. We report here our initial efforts toward the synthesis of the 2-Oxadecalin Spiroketal Core of Fusidilactone C featuring a Ketal-Tethered Intramolecular Diels-Alder Cycloaddition.