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.