Synthetic Studies of the Zoanthamine Alkaloids: Total Synthesis of Zoanthenol Based on an Isoaromatization Strategy

The total synthesis of zoanthenol, a unique aromatic member of the zoanthamine alkaloids, which has exhibited potent anti‐platelet activities on human platelet aggregation, is described in full detail. The key step involves a Brønsted acid‐promoted isoaromatization in the AB ring system to install the crucial aromatic ring. We have not only succeeded in the first total synthesis of zoanthenol, but also established an alternative efficient synthetic route from the commercially available norzoanthamine hydrochloride to zoanthenol. The mask of zoanthenol: The total synthesis of zoanthenol is described in full detail. Zoanthenol is an aromatic member of the zoanthamine alkaloids and it has potent anti‐platelet activity for human aggregation. The key step involves a Brønsted acid‐promoted isoaromatization in the AB ring system to install the crucial aromatic ring (see scheme).