Biomimetic Synthesis of Resorcylate Natural Products Utilizing Late Stage Aromatization: Concise Total Syntheses of the Marine Antifungal Agents 15G256ι and 15G256β

Diketo-1,3-dioxin-2-ones underwent retro-Diels−Alder reaction on heating in toluene at 110 °C to generate α,γ,ϵ-triketo-ketenes. These were trapped with alcohols to provide 2,4,6-triketocarboxylates, which were smoothly aromatized by sequential reaction with potassium carbonate and methanolic hydrogen chloride to give resorcylate esters. The reaction was applied in the total synthesis of the marine antifungal agents 15G256β (1), 15G256ι (2), and 15G256π (3) and the mycotoxin S-(−)-zearalenone (4).