Biomimetic synthesis of myrtucommulone K, N and O

A concise total synthesis of myrtucommulone K, N and O have been developed in 4 steps from commercially available materials. The synthetic strategy was inspired primarily by the biogenetic hypothesis and firstly enabled via a reduction, dehydration sequence for preparing isobutylidenesyncarpic acid followed by a hetero-Diels-Alder reaction to disclose the target moleculars. In this approach the exocyclic double bond of (−)-β-caryophyllene was more active than the endocyclic one in hetero-Diels–Alder reaction as the dienophile. The route is protecting-group-free, concise step, redox and pot economy.