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Synergistic Catalyst-Mediator Pairings for Electroreductive Cross-Electrophile Coupling Reactions
Jordan L S Zackasee1, Samir Al Zubaydi1, Blaise L Truesdell1
1Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
ACS Catalysis
|November 7, 2022
Summary
Mediator-assisted electrocatalysis significantly broadens the scope of electroreductive cross-electrophile coupling (eXEC). This approach enhances nickel-catalyzed reactions, enabling high yields for challenging substrates previously limited in scope.
Area of Science:
- Organic Chemistry
- Electrocatalysis
- Synthetic Methodology
Background:
- Electroreductive cross-electrophile coupling (eXEC) offers direct C-C bond formation between two electrophiles.
- Traditional eXEC reactions often exhibit limited substrate scope and lower yields compared to chemically mediated couplings.
Purpose of the Study:
- To develop a general strategy for enhancing the scope and efficiency of eXEC reactions using mediator-assisted electrocatalysis.
- To identify effective catalyst-mediator systems for challenging electrophile couplings.
Main Methods:
- Screening of various nickel-based catalysts and redox-matched mediators for eXEC reactions.
- Electrochemical and chemical reduction studies to evaluate catalyst-mediator system performance.
- Mechanistic investigations to understand catalyst-mediator interactions and optimize reaction conditions.
Main Results:
- Mediator addition dramatically improved yields in eXEC reactions catalyzed by nickel complexes, achieving near-quantitative product formation for challenging substrates.
- A library of effective catalyst-mediator systems was identified, demonstrating complementary reactivity across diverse substrate classes.
- Some optimized systems required electroreduction due to the low potentials needed for activation, highlighting the utility of electrocatalysis.
Conclusions:
- Mediator-assisted electrocatalysis is a powerful and general strategy to overcome the limitations of traditional eXEC.
- The developed catalyst-mediator systems provide a versatile toolkit for efficient C-C bond formation via electroreductive coupling.
- Mechanistic insights facilitate rational pairing of catalysts and mediators for future synthetic endeavors.
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