The effect of polymer-supported reagent structure on bromination of organic molecules
作者:Barbara Zajc、Marko Zupan
DOI:10.1016/s0040-4020(01)87938-2
日期:1990.1
reacted with hydrogen bromide or various alkyl bromides to pyridinium salts, which were further converted with chlorine to polymer supported reagents () containing up to 34% of chlorine, while substantial loss of bromide was observed during chlorination, debromination being diminished with increase in the length of the alkyl chain in the pyridinium salt. Polymeric reagents () converted 1,1-diphenylethene
交联聚(苯乙烯-共-4-乙烯基吡啶)与溴化氢或各种烷基溴化物到吡啶鎓盐,这是进一步与氯转化为聚合物负载的试剂(反应含有至多氯的34%),而观察到溴化物大量损失在氯化过程中,脱溴作用随吡啶鎓盐中烷基链长度的增加而减小。聚合试剂()将1,1-二苯乙炔转化为2-溴-1-氯-1,1-二苯乙炔和2-溴-1,1-二苯乙炔的结构,同时影响反应活性和加成比例消除过程。试剂的溴化能力是通过过量的1,1-二苯乙烯来确定的,并根据其结构进行变化。,范围为每克聚合试剂0.4-1.4 mmol。用聚合试剂对各种顺式和反式苯基酮进行溴氯化反立体定向,并遵循马尔可夫尼科夫类型的区域选择性,唯一的例外是(Z)-1-苯基丙烯,其中9%的区域异构体形成,而邻位溴化物氯化物伴随着高达7%的邻位二溴化物。异丙基苯中的溴化速度取决于试剂的结构以及对位/对位区域特异性,范围为3.6-4.0。