route, augmented by another cyclization within a nine-membered ring to afford a bicyclized product (4,4-dihalo-5-aryloctahydrocyclopenta[b]pyran). Easy transformation of the resulting geminal dihalide to a vinyl halide and a ketone further supplemented the substance of this approach.
报道了用
3-丁烯-1-醇对
环丙烷甲醛的单步TiX 4介导的Prins型环化反应,以相对立体地构建相对应变的(E)-六氢氧代
肟酸酯。将醇转换为3-butyn-1-ol引发了类似的路线,并在九元环内进行了另一个环化反应,从而得到了双环化产物(4,4-二卤代5-芳基氢环戊[ b ]
吡喃)。容易将生成的二卤代双卤化物转化为
乙烯基卤化物和酮,进一步补充了这种方法的实质。