Sun Guo-Quan, Zhang Wei, Liao Li-Li, Li Li, Nie Zi-Hao, Wu Jin-Gui, Zhang Zhen, Yu Da-Gang
Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China.
College of Pharmacy and Biological Engineering, Chengdu University, Chengdu, 610041, China.
Nat Commun. 2021 Dec 6;12(1):7086. doi: 10.1038/s41467-021-27437-8.
Electrochemical catalytic reductive cross couplings are powerful and sustainable methods to construct C-C bonds by using electron as the clean reductant. However, activated substrates are used in most cases. Herein, we report a general and practical electro-reductive Ni-catalytic system, realizing the electrocatalytic carboxylation of unactivated aryl chlorides and alkyl bromides with CO. A variety of unactivated aryl bromides, iodides and sulfonates can also undergo such a reaction smoothly. Notably, we also realize the catalytic electrochemical carboxylation of aryl (pseudo)halides with CO avoiding the use of sacrificial electrodes. Moreover, this sustainable and economic strategy with electron as the clean reductant features mild conditions, inexpensive catalyst, safe and cheap electrodes, good functional group tolerance and broad substrate scope. Mechanistic investigations indicate that the reaction might proceed via oxidative addition of aryl halides to Ni(0) complex, the reduction of aryl-Ni(II) adduct to the Ni(I) species and following carboxylation with CO.
电化学催化还原交叉偶联反应是利用电子作为清洁还原剂构建碳-碳键的强大且可持续的方法。然而，大多数情况下使用的是活性底物。在此，我们报道了一种通用且实用的电还原镍催化体系，实现了未活化芳基氯化物和烷基溴化物与一氧化碳的电催化羧基化反应。多种未活化的芳基溴化物、碘化物和磺酸盐也能顺利进行此类反应。值得注意的是，我们还实现了芳基（拟）卤化物与一氧化碳的催化电化学羧基化反应，避免了使用牺牲电极。此外，这种以电子作为清洁还原剂的可持续且经济的策略具有条件温和、催化剂廉价、电极安全便宜、官能团耐受性好以及底物范围广等特点。机理研究表明，该反应可能通过芳基卤化物向Ni(0)配合物的氧化加成、芳基-Ni(II)加合物还原为Ni(I)物种以及随后与一氧化碳的羧基化反应来进行。
