Sodium dithionite initiated addition of CF2Br2, CF3I and (CF3)2CFI to allylaromatics.: Synthesis and the reactivity of 4-aryl-1,1-difluorodienes and 4-aryl-1,1-bis(trifluoromethyl)dienes
Sodium dithionite initiated addition of CF2Br2, CF3I and (CF3)2CFI to allylaromatics.: Synthesis and the reactivity of 4-aryl-1,1-difluorodienes and 4-aryl-1,1-bis(trifluoromethyl)dienes
复制标题
DOI：
10.1016/j.jfluchem.2007.04.028
复制
发表时间：
2007-09-01
影响因子：
1.9
通讯作者：
Dmowski, Wojciech
中科院分区：
文献类型：
--
作者：
Ignatowska, Jolanta;Dmowski, Wojciech
在MeCN/H2O体系中，研究了连二亚硫酸钠引发CF2 Br 2、CF 3 I和（CF 3）（2）CFI对烯丙基苯末端双键的加成反应以及（CF 3）（2）CFI对烯丙基吡啶的加成反应。CF_2Br_2与烯丙基苯的反应得到相当量的加合物、1-（2，4-二溴-4，4-二氟丁基）苯、脱溴产物、1-（4-溴-4，4-二氟丁基）苯和二聚化合物，总收率40- 66%。加合物与DBU发生双脱卤化氢反应，得到4-芳基-1，1-二氟丁二烯，再与含氮亲双烯体发生Diels-Alder缩合反应，得到环上含二氟亚甲基的N-杂环化合物。CF_3 I和（CF_3）（2）CFI分别与烯丙基苯反应，主要产物为（4，4，4-三氟-2-碘丁基）苯和1-（4，5，5，5-四氟-4-三氟甲基）-2-碘戊基）苯。这些加合物的脱卤化氢分别以高产率得到（4，4，4-三氟丁-1-烯基）苯和4-芳基-1，1-双（三氟甲基）丁二烯。（CF_3）（2）CFI与烯丙基吡啶快速反应生成混合物，用DBU处理后，在约100 ℃下分离出4-吡啶基-1，1-双（三氟甲基）丁二烯。60%的收益。(c)2007 Elsevier B. V.保留所有权利。
Sodium dithionite initiated addition of CF2Br2, CF3I and (CF3)(2)CFI to the terminal double bond of allylbenzenes and of (CF3)(2)CFI to allylpyridines in a MeCN/H2O system were investigated. The reactions of CF2Br2 with allylbenzenes gave comparable amounts of adducts, 1-(2,4-dibromo-4,4-difluorobutyl)benzenes, debrominated products, 1-(4-bromo-4,4-difluorobutyl)benzenes, and dimeric compounds in total yields 40-66%. Treatment of the adducts with DBU resulted in double dehydrohalogenation affording 4-aryl-,1-difluorobutadienes which undergo Diels-Alder condensation with nitrogen dienophiles to give N-heterocycles with difluoromethylene group in the ring. The reactions of CF3I and (CF3)(2)CFI with allylbenzenes gave the respective adducts, (4,4,4-trifluoro-2-iodobutyl)benzenes and 1-(4,5,5,5-tetrafluoro-4(trifluoromethyl)-2-iodopentyl)benzenes as the main products. Dehydrohalogenation of these adducts resulted, respectively, in (4,4,4-trifluoro-but-l-enyl)benzenes and 4-aryl-1,1-bis(trifluoromethyl)butadienes in high yields. (CF3)(2)CFI reacted rapidly with allylpyridines to give mixtures from which, after treatment with DBU, 4-pyridyl-1,1-bis(trifluoromethyl)butadienes were isolated in a ca. 60% yield. (c) 2007 Elsevier B.V. All rights reserved.