Exceedingly Concise and Elegant Synthesis of (+)-Paniculatine, (−)-Magellanine, and (+)-Magellaninone

Starting from inexpensive (+)-pulegone as the chiral building block, a highly convergent synthesis of the unusual diquinane-based structures of (+)-paniculatine (1), (−)-magellanine (2), and (+)-magellaninone (3), has been achieved. This approach is based upon a tandem acylation–alkylation of ketoester 8 and palladium-catalyzed olefin insertion, oxidation, and hydrogenation for construction of the tetracyclic framework. This exceedingly concise strategy, requiring only 12–14 steps, is the shortest to date.