Rapid Construction of the Common [5–5–6] Tricyclic Ring Skeleton in Polycyclic Cembranoids and Norcembranoids via Intramolecular 1,3-Dipolar Cycloaddition

A synthetically challenging bowl-shaped [5-5-6] tricyclic framework commonly seen in many polycyclic cembranoids and norcembranoids was strategically established in a convenient six-step sequence featuring an intramolecular 1, 3-dipolar cycloaddition reaction. Synthetic manipulations of such a valuable intermediate were explored for future applications.