Aromatic Chlorosulfonylation by Photoredox Catalysis

Abstract

Visible-light photoredox catalysis enables the efficient synthesis of arenesulfonyl chlorides from anilines. The new protocol involves the convenient in situ preparation of arenediazonium salts (from anilines) and the reactive gases SO₂ and HCl (from aqueous SOCl₂ ). The photocatalytic chlorosulfonylation operates at mild conditions (room temperature, acetonitrile/water) with low catalyst loading. Various functional groups are tolerated (e.g., halides, azides, nitro groups, CF₃ , SF₅ , esters, heteroarenes). Theoretical and experimental studies support a photoredox-catalysis mechanism.

Keywords: aromatic substitution; photochemistry; photoredox catalysis; ruthenium; sulfonylation.