基于吡啶和1,3,5-三嗪的PNP钳状配体的设计合成以及在钴催化的末端炔烃半氢化反应中的应用  

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

作　　者：王银银 林晓婉 张飘 沈美华[1] 徐华栋[1] 徐德锋[1] Wang Yinyin;Lin Xiaowan;Zhang Piao;Shen Meihua;Xu Huadong;Xu Defeng(School of Pharmacy,Changzhou University,Changzhou,Jiangsu 213164)

机构地区：[1]常州大学药学院,江苏常州213164

出　　处：《有机化学》2021年第8期3312-3320,共9页Chinese Journal of Organic Chemistry

基　　金：国家自然科学基金(NO.21672027);江苏省高层次创新创业人才团队(No.2017-37)资助项目.

摘　　要：设计并合成了两类新型的PNP钳状配体,一类以吡啶结构为骨架,另一类以1,3,5-三嗪结构为骨架.将这两类配体应用于钴催化的硅氢还原末端炔烃N-(3-炔丁基)对甲苯磺酰胺(8a)的反应中,发现两者对反应速率和选择性均有重大影响.其中具有吸电子取代基的吡啶结构的配体2,6-双((S)-2-((二苯基膦)甲基)吡咯烷基)烟酸乙酯(L5b)可以高效促进8a的迁移半氢化反应,主要给出反式内烯产物.通过进一步筛选金属催化剂、溶剂和还原剂,确定了获得反式内烯产物的最优反应条件为CoCl_(2)/L5b/SiH(OMe)_(3)/四氢呋喃(THF).运用最优条件,研究了另外8种末端炔烃8b~8i的迁移半氢化反应,反应产物仍主要以反式内烯为主.简而言之,通过配体L5b发展了一种末端炔烃迁移还原的方法.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(8 a) 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(L5 b), which had pyridine skeleton with electron-withdrawing substituent, promoted the migratory semihydrogenation of 8 a giving E-2-alkene predominatly. Further screening of metal catalysts, solvents and reducing agents revealed that the optimal reaction condition was CoCl2/L5 b/Si H(OMe)3/trifluoroacetic acid(THF) for E-2-alkene product. More terminal alkynes 8 b~8 i were tested under the optimal reaction condition to afford E-2-alkene mainly. In brief, using ligand L5 b, a method of migratory semihydrogenation of terminal alkynes was developed.

关 键 词：PNP钳状配体 吡啶 1 3 5-三嗪 钴催化 末端炔烃 迁移半氢化反应 反式内烯 

分 类 号：O621.251[理学—有机化学] O641.4[理学—化学]