Late-stage sulfonic acid/sulfonate formation from sulfonamides via sulfonyl pyrroles

Sulfonamides are present in a range of useful molecules, such as drugs and agrochemicals. In recent years, the functionalization of sulfonamides via S–N bond cleavage has received increased attention. In this report, we detail an accessible and low-cost route for transforming primary sulfonamides into the corresponding sulfonic acids/sulfonates via sulfonyl pyrroles. The reaction is demonstrated with a range of substrates including aryl and alkyl sulfonamides, and in the late-stage functionalization of several sulfonamide-containing drug molecules.