Rapid enantioselective access to des-AB-trienic corticosteroids via intramolecular cycloaddition
Abstract
A short synthesis of an enantiomerically pure des-AB-trienic steroid 11 has been achieved by thermolysis of the optically active alkenic benzocyclobutene 9 obtained by selective nucleophilic addition of an isopropenyl group to the chiral epoxide 5 as a key step.