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Updated: Jan 13, 2026
Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
Published on: January 17, 2020
Mediator-Enabled Co-Catalyzed Z‑Selective Semihydrogenation via Hydride-Free Multisite Proton-Coupled Electron
Bryan Parnitzke1, Remy Lalisse2, Ethan Gerhardt1
1Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States.
This study introduces a tandem electrocatalytic method using a cobaltocene (Cp2Co) redox mediator and a cobalt precatalyst to selectively hydrogenate alkynes into cis-alkenes, offering a greener synthetic route.
Area of Science:
- Electrochemistry
- Organic Synthesis
- Catalysis
Background:
- Redox mediators are crucial for efficient electrochemical reactions, preventing electrode fouling and enabling reactions at lower potentials.
- Developing selective catalytic methods for alkyne hydrogenation is essential in organic synthesis.
Purpose of the Study:
- To develop a tandem electrocatalytic system for the selective hydrogenation of alkynes to cis-alkenes.
- To investigate the mechanism of this novel catalytic approach.
Main Methods:
- Controlled potential electrolysis (CPE) using a cobaltocene (Cp2Co) redox mediator and a (dppe)-CoCl2 precatalyst.
- Cyclic voltammetry (CV) and Density Functional Theory (DFT) calculations for mechanistic studies.
Main Results:
- Selective hydrogenation of various alkynes to cis-alkenes in moderate to good yields.
- High stereoselectivity for the Z isomer, especially with substrates containing tethered Lewis bases.
- Demonstrated application in the synthesis of combretastatin A-4.
- Successful gram-scale synthesis with up to 99% Faradaic efficiency.
Conclusions:
- The developed tandem electrocatalytic method provides an efficient and selective route for cis-alkene synthesis.
- The mechanism involves a hydride-free multisite proton-coupled electron transfer (MS-PCET) pathway.
- This methodology is applicable to complex natural product synthesis and scalable for practical applications.
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