Stereoselective synthesis of the spirocyclic ring system of the sesquiterpene spirolepechinene

Sesquiterpenes are a structurally diverse class of compounds that have been isolated from a wide range of living organisms. Spirolepechinene is a member of the rare spirojatamane class of sesquiterpenes with a unique relative stereochemistry about its spirocentre. While the other two members of this class have been synthesized, the differences in stereochemistry renders these previously-reported methods not applicable to the synthesis of spirolepechinene. Herein we present an efficient method for the synthesis of the spirocyclic core of spirolepechinene that produces the required stereochemistry for this unique natural product with high diastereoselectivity