Unified Strategy for the Synthesis of (−)‐Elisapterosin B and (−)‐Colombiasin A

A biomimetic [5+2] cyclization of a serrulatane diene (1) forms the basis of a concise synthesis of (−)-elisapterosin B. The diene 1 was prepared in 15 steps by using a Diels–Alder reaction between an oxygenated diene and a quinone, followed by the introduction of the methyl group at C3. The same diene 1 was used to prepare the natural product (−)-colombiasin A by a thermal [4+2] cycloaddition and demethylation.