Electrocatalytic Reduction of C–C π-Bonds via a Cobaltocene-Derived Concerted Proton–Electron Transfer Mediator: Fumarate Hydrogenation as a Model Study
Abstract
Reductive concerted proton–electron transfer (CPET) is poorly developed for the reduction of C–C π-bonds, including for activated alkenes that can succumb to deleterious pathways (e.g., a competing hydrogen evolution reaction or oligomerization) in a standard electrochemical reduction. We demonstrate herein that selective hydrogenation of the C–C π-bond of fumarate esters can be achieved via electrocatalytic CPET (eCPET) using a CPET mediator comprising cobaltocene with a tethered Brønsted base. High selectivity for electrocatalytic hydrogenation is observed only when the mediator is present. Mechanistic analysis sheds light on two distinct kinetic regimes based on the substrate concentration: low fumarate concentrations operate via rate-limiting CPET followed by an electron-transfer/proton-transfer (ET/PT) step, whereas high concentrations operate via CPET followed by a rate-limiting ET/PT step.
Additional Information
© 2021 American Chemical Society. Received: March 29, 2021; Published: June 17, 2021. The authors are grateful to the U.S. Department of Energy, Office of Basic Energy Sciences, for support via Grant DE-SC0019136 and also to the American Chemical Society Petroleum Research Fund (61951-ND3). J.D. thanks the Arnold and Mabel Beckman Foundation for a postdoctoral fellowship, and P.G.-B thanks the Ramón Areces Foundation for a postdoctoral fellowship. J.C.P. is grateful to the Resnick Sustainability Institute. We thank a reviewer for helpful feedback regarding proposed intermediates. Author Contributions. J.D. and P.G.-B. contributed equally. The authors declare no competing financial interest.Attached Files
Supplemental Material - ja1c03335_si_001.pdf
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Additional details
- Eprint ID
- 109602
- Resolver ID
- CaltechAUTHORS:20210626-183439518
- Department of Energy (DOE)
- DE-SC0019136
- American Chemical Society Petroleum Research Fund
- 61951-ND3
- Arnold and Mabel Beckman Foundation
- Fundación Ramón Areces
- Resnick Sustainability Institute
- Created
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2021-06-28Created from EPrint's datestamp field
- Updated
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2021-07-06Created from EPrint's last_modified field
- Caltech groups
- Resnick Sustainability Institute