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.
