By the effect of iodine, solid K2CO3 and a lipophilic quaternary ammonium salt phosphonoacetic acid allylic esters 4 were converted to cyclopropanephosphonic acid derivatives anellated to a five membered lactone ring 6 serving as good starting material for biologically active products. The reaction of cyclopropanation has been assumed to proceed by SET induced radical type elemental steps. Direct evidences
通过
碘的作用,固体K 2 CO 3和亲脂性季
铵盐
膦酰基乙酸烯丙基酯4被转化为
环丙烷膦酸衍
生物,其被芳香化为五元内酯环6,作为
生物活性产物的良好起始原料。已假定
环丙烷化反应是通过
SET诱导的自由基型元素步骤进行的。由ESR提供的直接证据表明,亲电基团11的封闭有6个内基的区域选择性。还观察到了
膦酸酯部分与
碘的有趣且新的交换反应。