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...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-. The treatment of tosylhydrazone 5, which was formed via the reaction of compound 4 and TsNHNH2 catalyzed by BF3-5Et2O, 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.展开更多
文摘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-. The treatment of tosylhydrazone 5, which was formed via the reaction of compound 4 and TsNHNH2 catalyzed by BF3-5Et2O, 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.
基金The work was supported bythe National High Technology Development Project(2001AA624030),the Natural Science Foundation of Guangdong Province(04300569),and the Youth Teacher Foundation of Sun Yat-Sen University(1131002).