Total Synthesis of Sollasin a and Sollasin d via Photocycloaddition of Methyl 2,4-Dioxopentanoate to Methyl E-2-Methyl-2-butenoate.

Starting from photocycloaddition of methyl 2,4-dioxopentanoate to methyl tiglate, an electron-deficient olefin, methyl-migrated monocyclofarnesyl sesquiterpenoids, d,l-sollasin a and d, anti-bacterial compounds, were synthesized.