文献类型：期刊文献

英文题名：A new and direct route to 3-fluoromethyl substituted pyrazol-4-acrylates via Pd-catalyzed C-H activation

作者：Wang, Xiaoguang[1,2];Fang, Xiang[1,2];Xiao, Hongyuan[1,2];Gong, Dongming[1,2];Yang, Xueyan[1,2];Wu, Fanhong[3]

机构：[1]E China Univ Sci & Technol, Adv Mat Lab, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, Sch Chem & Mol Engn, Inst Fine Chem, Shanghai 200237, Peoples R China;[3]Shanghai Inst Technol, Sch Chem & Environm Engn, Shanghai 200235, Peoples R China

年份：2013

卷号：69

期号：34

起止页码：6993

外文期刊名：TETRAHEDRON

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000322098000007)，CCR-EXPANDED(收录号:WOS:000322098000007)】；

基金：This work was supported by the National Natural Science Foundation of China (Nos. 21172148, 21202044) and Science and Technology Commission of Shanghai Municipality (No. 10540501300).

语种：英文

外文关键词：3-Fluoromethyl pyrazoles; Pd-catalyzed C4-H activation; Benzoquinone; Concerted metalation-deprotonation (CMD)

摘要：Direct C4-H activation of 3-fluoromethyl pyrazoles followed by an oxidative coupling with acrylates, which is perhaps the most direct method for the synthesis of 3-fluoromethyl substituted pyrazol-4-aciylates of biological interest, remains challenging. Here, the first example of the straightforward olefination via Pd-catalyzed C4-H activation of both C3-CF3 and C3-CF2H substituted pyrazoles is reported. The reaction of various C3-CF3 substituted pyrazoles with acrylates proceeds smoothly in the presence of Pd(OAc)(2) and Ag2CO3, whereas olefination of C3-CF2H substituted pyrazoles requires the addition of benzoquinone. A further computational study reveals that reactivity of the pyrazolyl substrates employed are strongly impacted by the substituents of different nature on their C1 or C5 position, which is in good agreement with the experimental data. (C) 2013 Elsevier Ltd. All rights reserved.