Synergistic Catalyst-Mediator Pairings for Electroreductive Cross-Electrophile Coupling Reactions.
Synergistic Catalyst-Mediator Pairings for Electroreductive Cross-Electrophile Coupling Reactions.
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DOI：
10.1021/acscatal.1c05144
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发表时间：
2022-01
期刊：
影响因子：
12.9
通讯作者：
Jordan L S Zackasee;Samir Al Zubaydi;Blaise L Truesdell;C. Sevov
中科院分区：
文献类型：
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作者：
Jordan L S Zackasee;Samir Al Zubaydi;Blaise L Truesdell;C. Sevov
电还原性交叉亲电体偶联（eXEC）代表了用于两种亲电体的直接C-C偶联的有吸引力的方法，但与使用化学还原剂的反应相比，其范围通常有限。这项工作表明，介体辅助电催化是增强eXEC反应的一般策略。虽然由各种广泛可用的配体-镍络合物催化的eXEC反应在应用于挑战性底物的还原偶联时产率低，但当包括氧化还原匹配的介体时，与相同络合物的反应以接近定量的产率产生产物。我们确定了一个库的催化剂介体系统，提供互补的反应性，并使耦合的范围内的底物类的高产率。这些催化剂体系适用于化学还原和电化学还原，但由于活化所需的低电位，一些催化剂体系需要电还原。最后，机理研究提供了促进催化剂-介体配对的见解。
Electroreductive cross-electrophile coupling (eXEC) represents an attractive approach for the direct C-C coupling of two electrophiles but generally suffers from limited scope compared to reactions with chemical reductants. This work demonstrates that mediator-assisted electrocatalysis is a general strategy for the enhancement of eXEC reactions. While eXEC reactions catalyzed by a variety of widely available ligand-nickel complexes are low yielding when applied to reductive couplings of challenging substrates, reactions with the same complexes generate products in near-quantitative yield when a redox-matched mediator is included. We identify a library of catalyst-mediator systems that provide complementary reactivity and enable coupling of a range of substrate classes in high yields. These catalyst systems are applicable to both chemical and electrochemical reduction, but some require electroreduction due to the low potentials required for activation. Finally, mechanistic studies offer insights that facilitate catalyst-mediator pairing.