甾体化合物D环结构对4-位二甲基化反应和3-位氧甲基化反应选择性的远程效应

The remote effect of D ring moiety on selectivity between 4-dimethylation and 3-O-methylation on steroidal compounds

目的在有4-烯-3-酮结构的甾体化合物4-位上引入二甲基。方法以7个带有4-烯-3-酮结构的甾体化合物为底物,按文献方法以相同的反应条件与碘甲烷-叔丁醇钾-叔丁醇反应系统反应。结果4个底物反应结果和文献一致,顺利得到了4-位二甲基化的产物,而另外3个底物则以高收率转化成为3-位氧甲基化的产物。结论7个甾体底物A、B、C3个环的结构基本一致,只是D环的结构不同,所以这7个化合物的不同反应结果表明甾体D环结构通过远程效应对4-位二甲基化和3-位氧甲基化反应的选择性产生了影响。

Objective To introduce dimethyl on 4-position of 4-ene-3-one steroids. Methods Seven 4-ene-3-one steroids were treated with methyl iodide （CH3I） and potassium tert-butoxide （t-BuOK） in tert-butanol （t-BuOH）. Results Four substrates were smoothly converted to 4,4-dimethyl products, while other three substrates afforded 3-O-methylation products with high yields. Conclusions The different reaction results revealed a high remote effect of D ring moiety on the selectivity between 3-O-methylation and 4-dimethylation.