关键词: 桉烷, 5&alpha, 11-二羟基-2-氧代桉烷-3-烯, 全合成, 倍半萜

Abstract: The first total synthesis of (+)-5α-hydroxy-isopterocarpolone (1), an oxygenated eudesmane isolated from Chinese folk medicine Artemisia eriopoda, starting from (+)-dihydrocarvone(2) was described. Compound 4 was stereoselectively prepared from compound 2 in three steps according to reference[7]. The treat_ment of tosylhydrazone 5, which was formed via the reaction of compound 4 and TsNHNH₂ catalyzed by BF₃·Et₂O, with an excess of n-butyllithium gave triene 6. Oxidation of triene 6 with singlet oxygen afforded the desired endo-peroxide 7 as a single product. Reductive cleavage of peroxide 7 with K₂CO₃ gave α-rotunol 3, a natural eudesmane firstly isolated in 1969. Hydrolysis of α-rotunol 3 with 10% sulfuric acid afforded (+)-5α-hydroxy-isopterocarpolone (1). The structures of all the compounds were confirmed by IR, MS and NMR spectra.

Key words: Eudesmane, 5α-Hydroxy-isopterocarpolone, Total synthesis, Sesquiterpene