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α-Amido Sulfonium Salts Provide a Platform for Photocatalytic Metal-Free Carbon–Carbon Bond Formation in Amides

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide α-Amido sulfonium salts are bench-stable precursors of α-amidyl radicals, prepared directly from tertiary amides. These largely unexplored sulfonium salts engage in metal-free photocatalytic C(sp 3 )–C(sp 2 ) and C(sp 3 )–C(sp 3 ) bond formation in cross-coupling reactions that realize the formal α-alkylation, α-alkenylation, and α-arylation of amides. Fine-tuning the photocatalytic conditions allows divergent access to important 1,4-dicarbonyl compounds, skipped unsaturated amides, and α-heteroarylated amides, thus showcasing the role of α-amido sulfonium salts in establishing a novel platform for amide functionalization. Preliminary mechanistic experiments support a photocatalytic cycle in which the sulfonium salts are reduced to form α-amidyl radicals that couple with various electron-rich partners in a chemodivergent approach for the introduction of complexity in amides.

Source: ACS Catalysis

DOI: 10.1021/acscatal.5c02029

Authors: Leendert van Dalsen, Shibo Zhang, Wei Tian, Ben W. Joynson, Ciro Romano, David J. Procter

Institution: University of Manchester

Language: English

Topic: Radical Photochemical Reactions

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funders: Leverhulme Trust, University of Manchester, Engineering and Physical Sciences Research Council