1,1-, 1,2-, and 1,4-Eliminations from the Corresponding Dihalogenated Compounds Using Bu_3SnSiMe_3-F^-

我们已经报道了在DMF中由Me_3SiSnBu_3在CSF存在下生成锡基阴离子，并利用这种锡基阴离子通过卤素-金属交换反应进行新的环化反应。预期活性中间体将通过1，1-，1，2-或1，4-消除反应生成相应的二卤代化合物。首先，在甲基丙烯酸甲酯存在下，用Me_3SiSnBu_3和CSF在DMF中与α，α‘-二溴邻二甲苯反应，以87%的产率得到2-甲氧基四氢萘。以类似的方法，以良好的产率获得了各种四氢萘衍生物。另一方面，苯是由1，2-二溴苯制得的。该反应进一步用于由1，1-二溴烯合成亚烷基卡宾，并可由相应的1，1-二溴烯以较好至中等的产率得到烯烃或环戊酮的衍生物。

We have already reported the generation of stannyl anion from Me_3SiSnBu_3 in the presence of CsF in DMF and the utilization of this stannyl anion for the novel cyclization via halogen-metal exchange reaction. It was expected that the active intermediates would be produced from the corresponding dihalo-compounds by 1,1-, 1,2-, or 1,4-elimination. At first, when alpha, alpha'-dibromo-o-xylene was treated with Me_3SiSnBu_3 and CsF in the presence of methyl acrylate in DMF,2-carbomethoxy tetrahydronaphthalene was obtained in 87% yield. In a similar manner, the various tetrahydronaphthalene derivatives were obtained in good yields. On the other hand, benzyne was produced from 1,2-dibromobenzene. This reaction was further developed for the generation of alkylidene carbene from 1,1-dibromoalkene, and we could obtained alkenes or cyclopentenone derivatives from the crresponding 1,1-dibromoalkene in good to moderate yields.