5α,11-二羟基-2-氧代桉烷-3-烯的全合成

5α，11-二羟基-2-氧代桉烷-3-(5α-Hydroxy—isopterocarpolone，1)是由贾忠建等于1996年从中药南牡蒿中首次分离得到的一种桉烷型倍半萜类天然产物．桉烷型倍半萜类化合物广泛分布于天然植物中，具有较好的昆虫拒食、抑制细胞繁殖和植物生长调节等多种生理活性．天然产物1的合成研究尚未见报道．

Total Synthesis of 5α-Hydroxy-isopterocarpolone

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 reference7]. The treatment 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.