New members of the caryophyllene family via biomimetic π-cyclizations and consecutive transformations

Abstract A series of derivatives from caryophyllene oxide have been prepared in enantiomerically pure form, including bicyclic, tricyclic and tetracyclic sesquiterpenes and sesquiterpenoids. A key intermediate is the unsaturated, chiral (pro 1S,8Z)-bridgehead carbocation 5 and its monobrominated derivative 5a .