Modular Total Syntheses of Hyperforin, Papuaforins A, B, and C via Gold(I)-Catalyzed Carbocyclization

The
remarkable biological activities of polyprenylated polycyclic acylphloroglucinols
(PPAPs) combined with their highly oxygenated and densely functionalized
frameworks have stimulated the interest of synthetic organic chemists
over the past decade. Herein, we report the concise total syntheses
of four natural products PPAPs, of which some have antibacterial properties,
notably hyperforin and papuaforin A. The salient features of this
strategy are the short and gram-scalable synthesis of densely substituted
PPAPs scaffolds via a Au­(I)-catalyzed carbocyclization and the late-stage
functionalization for a unified access to a wide variety of PPAPs