First enantiospecific synthesis of marine sesquiterpene quinol akaol A

The first enantiospecific synthesis of akaol A, a marine sesquiterpene quinol, has been achieved. Key steps of the synthetic sequence are the oxidative degradation of (-)-sclareol to a dinorlabdane ketoester, mediated by the ozone-lead(IV)) acetate system, the diastereoselective a-methylation of a ketoaldehyde, followed by an intramolecular aldol condensation and the further Die Is-Alder cycloaddition of a dienol ether.