1997 terpenes

terpenesU 0200

12 - 176Use of Conjugated Dienones in Cyclialkylations: The Total Synthesesof (±)-Barbatusol, (±)-Pisiferin, (±)-Deoxofaveline, (±)- Xochitlolone,and (±)-Faveline. — The racemic tricyclic triterpenoids barbatusol (V),pisiferin (VI), deoxyfaveline (VIIa), faveline (VIIb), and xochitlolone (VIII) aresynthesized in 15, 11, 13, 2, and 7% overall yields, resp., via cyclialkylation of afunctionalized arene containing a Lewis acid activated conjugated dienone, e.g.(II), as key step. — (MAJETICH, G.; HICKS, R.; ZHANG, Y.; TIAN, X.;FELTMAN, T. L.; FANG, J.; DUNCAN, S. JUN.; J. Org. Chem. 61 (1996) 23,8169-8185; Dep. Chem., Univ. Ga., Athens, GA 30602, USA; EN)

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