Enantioselective Total Synthesis of (+)-Aberrarone

We disclose the first total synthesis of (+)-aberrarone, a diterpenoid natural product featuring a 5-5-5-6-fused tetracyclic skeleton. Key to the approach is a Au-catalyzed-Sn-mediated Meyer-Schuster-Nazarov-cyclopropanation-aldol cascade, which closes four rings in high yield. The convergent approach furnishes the natural product (+)-aberrarone stereoselectively in 15 steps. We highlight the benefits of using a Sn-alkoxide to considerably expand the opportunities of Au-catalysis for the synthesis of complex molecules.