Coordination Sphere Control Enables Hydride-Free Tandem Electrocatalytic E-Selective Semi-Hydrogenation
4 affiliations
- 1Department of Chemistry
- 2Boston University
- 3Department of Chemistry and Biochemistry
- 4University of California
Abstract
Hydride-free electrocatalytic semi-hydrogenation offers an alternative to metal-hydride-based platforms, yet controlling alkene stereochemistry through such pathways remains challenging. Herein, we report an E-selective, redox-mediated Co-catalyzed platform enabled by cooperative control of the catalyst coordination sphere via ligand denticity and acid identity. Using a triphosphine ligand and ammonium chloride acid reverses the stereochemical preference of a previously developed Z-selective system, providing access to a range of E-alkenes in high yields and excellent stereoselectivity (up to 92% yield and >20:1 E:Z). Experimental and computational mechanistic studies support a mechanism involving a distinct proton transfer step with a chloride-mediated organization of the ammonium proton donor and Co catalyst. This allows for an initial inner-sphere protonation prior to cobaltocene-mediated reduction of the resultant Co(III)-alkenyl intermediate, followed by subsequent outer-sphere protonation to yield trans alkenes. These findings illustrate that coordination-sphere organization and precise control of proton transfer pathways may serve as complementary design principles in stereoselective electrocatalysis.
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BibTeX
@misc{parnitzke2026coordination,
title = {{Coordination Sphere Control Enables Hydride-Free Tandem Electrocatalytic E-Selective Semi-Hydrogenation}},
author = {Bryan Parnitzke and Yaning Liu and Lupita S. Ramirez and Osvaldo Gutierrez and Joseph Derosa},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010969/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010969/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Coordination Sphere Control Enables Hydride-Free Tandem Electrocatalytic E-Selective Semi-Hydrogenation
AU - Bryan Parnitzke
AU - Yaning Liu
AU - Lupita S. Ramirez
AU - Osvaldo Gutierrez
AU - Joseph Derosa
PY - 2026
DA - 2026/10/23
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010969/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010969/v1
AB - Hydride-free electrocatalytic semi-hydrogenation offers an alternative to metal-hydride-based platforms, yet controlling alkene stereochemistry through such pathways remains challenging. Herein, we report an E-selective, redox-mediated Co-catalyzed platform enabled by cooperative control of the catalyst coordination sphere via ligand denticity and acid identity. Using a triphosphine ligand and ammonium chloride acid reverses the stereochemical preference of a previously developed Z-selective system, providing access to a range of E-alkenes in high yields and excellent stereoselectivity (up to 92% yield and >20:1 E:Z). Experimental and computational mechanistic studies support a mechanism involving a distinct proton transfer step with a chloride-mediated organization of the ammonium proton donor and Co catalyst. This allows for an initial inner-sphere protonation prior to cobaltocene-mediated reduction of the resultant Co(III)-alkenyl intermediate, followed by subsequent outer-sphere protonation to yield trans alkenes. These findings illustrate that coordination-sphere organization and precise control of proton transfer pathways may serve as complementary design principles in stereoselective electrocatalysis.
ER -