Total Synthesis of ( ± )-α-Cubebene and ( ± )-β-Cubebene

Abstract

An efficient total synthesis of the racemic forms of the novel tricyclic sesquiterpenes α-cubebene (1) and β-cubebene (2) is described. The key step of this synthesis involved the cupric sulfate catalyzed intramolecular cyclization of the olefinic diazoketone 3, which produced, in high yield, ( ± )-β-cubebene norketone (24) and ( ± )-1,6-epi-β-cubebene norketone (25), in a ratio of approximately 3:5, respectively.