Oxidative dearomatization/intramolecular Diels-Alder cycloaddition cascade for the syntheses of (±)-atisine and (±)-isoazitine.

A convergent and efficient formal synthesis of (±)-atisine has been accomplished. The synthetic strategy is to efficiently construct the bicyclo[2.2.2]octane ring moiety by an oxidative dearomatization/intramolecular Diels-Alder cycloaddition cascade. The first total synthesis of another atisine-type C(20)-diterpenoid alkaloid, (±)-isoazitine, has also been achieved employing the same strategy.