Closing the Carbon Loop: Continuous-Flow Synthesis of N-Aroyl Sulfoximines via Electrochemical CO2 Reduction

Sulfoximines have emerged as versatile scaffolds in modern synthesis, medicinal chemistry, and catalysis due to their tunable electronic and steric properties. In particular, N-aroyl sulfoximines are valuable intermediates in amide coupling, C-H functionalization, and heterocycle formation. However, conventional synthetic approaches often rely on stoichiometric activating reagents and harsh conditions, generating waste and limiting substrate scope. Herein, we report a sustainable continuous-flow platform for the Pd-catalyzed carbonylative N-aroylation of sulfoximines employing carbon monoxide (CO) as a C1 source under mild conditions. The system integrates a solid oxide electrolysis cell (SOEC) to generate dry CO from CO2 on-demand, enabling a safe, modular, and atom-economical transformation. The process displayed broad substrate tolerance, accommodating electron-rich, electron-poor, and heteroaromatic aryl iodides to furnish N-aroyl sulfoximines in 50%–99% isolated yields within 40 min at 80°C and 6 bar. A heterogeneous Pd-based catalyst, covalently immobilized on Merrifield resin, further enabled efficient flow operation with 96% conversion, facilitating the catalyst recovery. Finally, the adoption of Cyrene, a biomass-derived solvent, afforded quantitative yields and demonstrated the process compatibility with green solvents. This work establishes a scalable, safe, and sustainable strategy for sulfoximine N-aroylation, integrating CO2 valorization, continuous-flow technology, and heterogeneous catalysis for modern carbonylation chemistry.

• Moroni G¹
• Weiss M¹
• Russo G^1,2
• Biscontini G¹
• Lanaridi O¹
• Limbeck A¹
• Huber T¹
• Opitz AK¹
• Bica-Schröder K¹

•   ¹Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria
• ²Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy

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