Foscarnet is an important antiviral drug with significant clinical value. However, its conventional synthetic routes generally involve multiple steps, high costs, and hazardous reagents, making the development of a simple and efficient synthesis highly desirable. Electrosynthesis using CO₂ and Na₂HPO₃ as feedstocks offers a promising approach to overcoming the limitations of traditional routes. Nevertheless, both CO₂ and HPO₃²⁻ are chemically stable, and the reaction requires coordinated anodic and cathodic processes, making their direct coupling to form a C–P bond particularly challenging.

Buxing Han and Xinchen Kang's team at the Institute of Chemistry of the Chinese Academy of Sciences (ICCAS) has developed a new ionic-liquid-radical-mediated C–P coupling pathway and achieved the electrocatalytic synthesis of foscarnet from CO₂ and HPO₃²⁻ at room temperature.

The study showed that, during electrolysis, Bpy+ cations on the surface of the IL@Bi catalyst are reduced to Bpy• radicals. These radicals subsequently transfer electrons spontaneously to CO₂, generating CO₂•− radicals and thereby markedly increasing the concentration of CO₂•− in solution. The CO₂•− radicals then undergo C–P coupling with PO₃•²⁻ radicals generated at the anode, enabling efficient electrosynthesis of foscarnet. In this system, a maximum Faradaic efficiency of 37.5% for foscarnet was achieved with a current density of up to 224.2 mA cm⁻². This strategy not only provides a new approach for the co-conversion of CO₂ and HPO₃²⁻ under mild conditions, but also offers new insights into the design of other efficient electrocatalytic reaction systems.

The work was recently published in Nature Catalysis (Nat. Catal., 2026, doi:10.1038/s41929-026-01608-6). Ph.D. student Hengan Wang is the first author, and Prof. Xinchen Kang and Prof. Buxing Han are the corresponding authors.

Electrocatalytic coupling of CO₂ and HPO₃²⁻

(Image by WANG Hengan)

Contact:

Prof. KANG Xinchen

Institute of Chemistry, Chinese Academy of Sciences

Email: kangxinchen@iccas.ac.cn

Keywords: ionic liquid radicals; relayed electron transfer; C–P coupling; foscarnet electrosynthesis