Structures and synthesis of some new antibacterial sesquiterpenoids from the gorgonian coral Pseudopterogorgia rigida

The antibacterial properties of extracts of the Caribbean gorgonian Pseudopterogorgia rigida have been shown to originate in three previously undescribed derivatives of the aromatic sesquiterpene α-curcumene. (?)-Curcuphenol, (?)-curcuquinone, and (?)-curcuhydroquinone were isolated in high yield (30% extract) and structurally defined by inter-conversion and by reduction of the mesylate derivatives to yield the parent hydrocarbon (?)α-curcumene. A high yielding synthesis (86% overall) of curcuphenol, the most active antibacterial metabolite, is described.