Biomimetic Synthesis of (+)-Ledene, (+)-Viridiflorol, (-)-Palustrol, (+)-Spathulenol, and Psiguadial A, C, and D via the Platform Terpene (+)-Bicyclogermacrene

(+)-Bicyclogermacrene is a strained bicyclic and common sesquiterpene found in several essential oils. A short and good yielding synthesis of bicyclogermacrene proceeding in seven steps is reported. This terpene is used as key platform intermediate for a biomimetic access to several aromadendrene sesquiterpenoids, such as ledene, viridiflorol, palestrol, and spathulenol. Furthermore, bicyclogermacrene is shown to be the terpene component in the synthesis of the meroterpenoids psiguadial A, C, and D.