16α-溴-17-羟基对映贝壳杉烷类化合物的合成

Synthesis of 16α-Bromo-17-Hydroxyl-ent-Kauranoid

贝壳杉烯化合物。在以甜叶菊甙(stevioside,2)为原料在进行对映贝壳杉烯二萜的合成研究中,我们试图合成1及其衍生物3和4以进行抗旱孕活性试验及构效关系的研究。 合成的关键是引进C_(9.11)双键,此可通过C_(17)—OH先引入C_(11)—OH,然后脱羟而成。文献曾报道几乎定量地将17羟基对映贝壳杉—19—酸甲酯(5)转化成C_(11,17)环醚化合物 6(Scheme1)。

Two 16α-bromo-17-hydroxyl-ent-kauranoids, 7 and 8 as cyclization precursor were synthesized. SeO2 oxidation of the allylic compound 10 didn't give the allylic aldehyde compound 11, but an 13-acetyl rearangement product 12 was obtained.