Chin. J. Org. Chem. ›› 2019, Vol. 39 ›› Issue (2): 482-490.DOI: 10.6023/cjoc201807050 Previous Articles     Next Articles

Special Issue: 碳氢活化合辑2018-2019

ARTICLE

Pd/1,3-双(二苯基膦)丙烷催化苯并噁唑C-2位直接芳基化反应的研究

汪洋点点, 余晓军, 付海燕, 郑学丽, 陈华, 李瑞祥   

  1. 四川大学化学学院 教育部绿色化学和技术重点实验室 成都 610064
  • 收稿日期:2018-07-27 修回日期:2018-09-05 出版日期:2019-02-25 发布日期:2018-09-10
  • 通讯作者: 李瑞祥 E-mail:liruixiang@scu.edu.cn
  • 基金资助:

    国家自然科学基金(Nos.21572137,21871187)、四川省科技厅基金(No.2018GZ0312)资助项目.

Pd/1,3-Bis(diphenylphosphino)propane Catalyzed Arylation of Benzoxazoles at C-2 Position with Aryl Bromides

Wang Yangdiandian, Yu Xiaojun, Fu Haiyan, Zheng Xueli, Chen Hua, Li Ruixiang   

  1. Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064
  • Received:2018-07-27 Revised:2018-09-05 Online:2019-02-25 Published:2018-09-10
  • Contact: 10.6023/cjoc201807050 E-mail:liruixiang@scu.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21572137, 21871187), the Key Program of Sichuan Science and Technology Project (No. 2018GZ0312).

A catalyst system combined of PdCl2 with 1,3-bis(diphenylphosphion)propane (dppp), which was simple and from commercially available materials, was reported for the highly efficient arylation of benzoxazoles at C-2 position with aryl bromides. This catalytic system could tolerate a great number of functional groups in benzoxazole and bromobenzene. With a low PdCl2 loading of 0.01 mol%, aryl bromides could be completely converted into the desired products for 24 h. If the loading of catalyst was up to 0.10 mol%, most of substrates could give more than 90% yields in 6 h. The exploration of the reaction mechanism discovered that Pd nanoparticles were formed during this reaction. The morphology and composition analysis of the Pd nanoparticles with transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) indicated that dppp played a key role to block the aggregation of palladium particles. In addition, the ring-opening pathway of benzoxazoles in the reaction process was proved by control experiments. Hot filtration experimental and high resolution mass spectrum (HRMS) analysis of filtrate suggested that the real active species were Pd(0)-Pd(Ⅱ)/dppp complexes.

Key words: arylation, benzoxazole, 1,3-bis(diphenylphosphion)propane, palladium