Enantiospecific synthesis of antifungal dasyscyphin E from cupressic acid

Abstract The first synthesis of the sesquiterpene quinol dasyscyphin E has been achieved starting from cupressic acid. Key steps of the synthetic sequence are the oxidative degradation of the diterpene side chain to give a methylketone, the diastereoselective α-methylation of a protected ketoaldehyde, the subsequent intramolecular aldol condensation and the further Diels-Alder cycloaddition of a dienol ester.