摘要
三氟乙酸钠在以CuI为催化剂的条件下与卤代芳烃进行取代反应,生成相应的三氟甲基化合物。研究了含有不同吸电性能取代基的卤代芳烃三氟甲基化反应的速率常数及转化率,实验结果表明硝基取代的卤代芳烃的反应活性较高,而含有甲基等供电性取代基的卤代芳烃的反应活性较低。结合Hammett关联曲线分析后认为,该反应过程中首先生成有效的三氟甲基阴离子中间体CF3CuI-,该中间体然后与卤素取代基发生亲核取代反应。
In the presence of copper（ Ⅰ ） iodide as catalyst,aromatic halides could be trifluoromethylated by sodium trifluoroacetate to give the corresponding trifluoromethylated compounds. The rate constants and yields of aromatic halides containing substitutes with different electrophilicities were investigated. The resuits showed that electron-withdrawing nitro substituent favored the reaction while methyl group exhibited inhibition. Consideration of the correlation of the reactivity of different aromatic halides analyzed through the Hammett plot led to form a possible intermediate CF3CuI^-, an equivalent of trifluoromethyl anion, which then underwent the nucleophilic substitution of halide group.
出处
《化学试剂》
CAS
CSCD
北大核心
2005年第8期453-455,共3页
Chemical Reagents
