Chinese Journal of Organic Chemistry ›› 2021, Vol. 41 ›› Issue (8): 3312-3320.DOI: 10.6023/cjoc202102050 Previous Articles     Next Articles



王银银, 林晓婉, 张飘, 沈美华, 徐华栋*(), 徐德锋*()   

  1. 常州大学药学院 江苏常州 213164
  • 收稿日期:2021-02-26 修回日期:2021-04-09 发布日期:2021-05-25
  • 通讯作者: 徐华栋, 徐德锋
  • 基金资助:
    国家自然科学基金(21672027); 江苏省高层次创新创业人才团队(2017-37)

Design and Synthesis of Pyridine and 1,3,5-Triazine PNP Pincer Ligands and Their Application in Cobalt Catalyzed Semihydrogenation of Terminal Alkynes

Yinyin Wang, Xiaowan Lin, Piao Zhang, Meihua Shen, Huadong Xu(), Defeng Xu()   

  1. School of Pharmacy, Changzhou University, Changzhou, Jiangsu 213164
  • Received:2021-02-26 Revised:2021-04-09 Published:2021-05-25
  • Contact: Huadong Xu, Defeng Xu
  • Supported by:
    National Natural Science Foundation of China(21672027); High-Level Entrepreneurial Talent Team of Jiangsu Province(2017-37)

Two types of novel PNP pincer ligands were designed and synthesized. One had a pyridine core and the other had a 1,3,5-triazine. Evaluation of these ligands in cobalt catalyzed semihydrogenation by silane of terminal alkyne N-(but-3- yn-1-yl)-4-methylbenzenesulfonamide (8a) was carried out, in which both had significant effects on the reaction rate and selectivity. Ethyl 2,6-bis((S)-2-((diphenylphosphanyl)methyl)pyrrolidin-1-yl)nicotinate (L5b), which had pyridine skeleton with electron-withdrawing substituent, promoted the migratory semihydrogenation of 8a giving E-2-alkene predominatly. Further screening of metal catalysts, solvents and reducing agents revealed that the optimal reaction condition was CoCl2/L5b/ SiH(OMe)3/trifluoroacetic acid (THF) for E-2-alkene product. More terminal alkynes 8b~8i were tested under the optimal reaction condition to afford E-2-alkene mainly. In brief, using ligand L5b, a method of migratory semihydrogenation of terminal alkynes was developed.

Key words: PNP pincer ligand, pyridine, 1,3,5-triazine, cobalt catalysis, terminal alkyne, migratory semihydrogenation, E-2-alkene