有机化学 ›› 2017, Vol. 37 ›› Issue (1): 190-195.DOI: 10.6023/cjoc201607005 上一篇    下一篇

研究论文

零价钯和苯甲酸共催化内炔烃氢胺化反应机理的理论研究

卞荣剑, 鲍晓光   

  1. 苏州大学材料与化学化工学部 苏州 215123
  • 收稿日期:2016-07-04 修回日期:2016-08-28 出版日期:2017-01-25 发布日期:2016-09-01
  • 通讯作者: 鲍晓光 E-mail:xgbao@suda.edu.cn
  • 基金资助:

    国家自然科学基金(No. 21302133)资助项目.

Computational Insights into the Mechanism of Pd(0) and Ben-zoic Acid Co-Catalyzed Hydroamination of Internal Alkynes

Bian Rongjian, Bao Xiaoguang   

  1. College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123
  • Received:2016-07-04 Revised:2016-08-28 Online:2017-01-25 Published:2016-09-01
  • Supported by:

    Project supported by the National Natural Science Foundation of China(No. 21302133).

通过密度泛函方法(DFT)研究了零价钯和苯甲酸共催化内炔烃氢胺化反应的机理.计算研究表明,文献中推测的通过苯甲酸的O-H键氧化加成到零价钯上形成钯氢中间体并不是启动该反应的有利途径.机理如下:在零价钯炔烃复合物上,苯甲酸可以通过质子转移到炔烃的途径得到二价烯基钯中间体,生成的羧酸根阴离子可以进一步辅助底物发生β-氢消除反应生成联烯中间体,随后在零价钯联烯复合物上,再次通过苯甲酸质子转移得到烯丙基钯中间体,最后胺亲核进攻烯丙基末端碳得到最终氢胺化产物.

关键词: 钯催化, 羧酸, 密度泛函, 氢胺化, 反应机理

Computational studies were carried out to investigate the detailed mechanism of Pd(0) and benzoic acid co-catalyzed hydroamination of internal alkynes.In the presence of the benzoic acid,the formation of a hydridopalladium intermediate via the oxidative addition(OA) of the O-H bond of benzoic acid into the Pd(0) complex center might not be a favorable reaction pathway to start the reaction.Instead,after the coordination of benzoic acid with the Pd(0)-alkyne complex,a proton transfer process from the acid to carbon of alkyne is found to be a favorable pathway,leading to the alkenyl(PhCOO) Pd(Ⅱ) intermediate.Next,the resulting alkenyl(PhCOO) Pd(Ⅱ) species would produce phenylallene intermediate via a β-H elimination step assisted by the formed benzoate anion.Subsequently,the benzoic acid might undergo a second proton step to the phenylallene intermediate to produce the π-allylpalladium species.Finally,the amine substrate could undergo a nucleophilic addition to the terminal carbon of the π-allylpalladium species to produce the hydroamination product.

Key words: Pd catalysis, carboxylic acid, DFT, hydroamination, reaction mechanism