Work

Use of Electron-Transfer Mediators to Access Higher Electrochemical Current Densities in Ni-Catalyzed Cross-Electrophile Coupling

Year: 2025

Type: article

Abstract: Ni-catalyzed cross-electrophile coupling (XEC) reactions are versatile methods for carbon–carbon bond formation, and they often use electrochemistry to supply the requisite electrons. These reactions, however, typically exhibit slow rates and operate at low current densities (e.g., 1–4 mA/cm 2 ) to avoid formation of undesirable side products. Here, we show that much higher current densities and reaction selectivity can be accessed by using a homogeneous electron-transfer (ET) mediator. Bis(ethylcyclopentadienyl)cobalt(II), which has a redox potential similar to that of the bipyridyl-ligated Ni catalyst (−1.45 and –1.50 V vs Fc/Fc +, respectively), exhibits the best performance. This ET-mediator strategy is applied to numerous C(sp 2 )–C(sp 3 ) coupling reactions and extended to a flow-based reaction on 10 mmol-scale that proceeds in 96% yield with 91% Faradaic efficiency at a current density of 18 mA/cm 2 .

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.5c10599

Authors: Jieru Zhu, Shannon S. Stahl

Institution: University of Wisconsin–Madison

Language: English

Topic: Catalytic Cross-Coupling Reactions

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funders: National Science Foundation, National Institutes of Health, National Institute of General Medical Sciences