The Development of Strategies for the Elaboration of Linear Triquinane Sesquiterpenoids: Hypnophilin and Ceratopicanol as Exemplary Case Studies

Linear triquinanes, those tricyclopentanoid systems that feature three five-membered rings fused together in an extended fashion, constitute a particularly interesting class of sesquiterpenoid natural product. The uniqueness of their architecture, the challenge of adroitly introducing the pendant methyl groups, and the proper resolution of those special problems associated with the regiocontrolled introduction of oxygen functionality have attracted many practitioners of organic synthesis. The result has been the development of novel synthetic strategies and the resourceful application of new reactions.This review focuses on two target molecules, hypnophilin and ceratopicanol, and contrasts the several synthetic routes that have been reported for their de novo synthesis. Attention is directed in particular to the global efficiency of each approach.