Caryophyllane, Humulane, and Related Sesquiterpenoids

Force field calculations have been applied to caryophyllene and four basic conformed (286)—(289) have been identified of which (286) and (288) contribute 75 % and 

Shirahama, E. Osawa, B. R. Chhabra, T. Shimokawa, T. Yokono, T. Kanaiwa, T. Amiya, and T. Matsumoto, Tetrahedron Lett., 1981, 22, 1527. 

The number of sesquiterpenoids which can be formally derived from a caryo-phyllene-type precursor has risen quite dramatically in the last few years and includes the following structural types - 

A new addition to this ever-growing group is senecrassidiol (302) which has been isolated from Senecio crassissimus and it has been suggested that this compound with its unusual cis ring fusion may be formed from the co-metabolite (303) by transannular hydration.59 Previously Bohlmann and Zdero153 had identified the rare epi-caryophyllene (304) in Euryops brevipapposus and converted it into 

Turning now to the intriguing propellane sesquiterpene modhephene (308), Karpf and Dreiding159 have provided full details of their original synthesis. Hot 

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