Electrochemical Dehydration of Sulfonic Acids to Their Anhydrides.

We developed an electrochemical method for sulfonic anhydride synthesis and one-pot derivatization into sulfonamides and mesylates under mild conditions. Aliphatic sulfonic anhydrides were electrogenerated in up to a 74% yield. Since isolating these moisture-sensitive intermediates is challenging, the in situ-generated sulfonic anhydrides were directly converted into sulfonamides or alkyl sulfonates using amines or alcohols, respectively. This scalable process enables the synthesis of various nitrogen- and oxygen-based products in the multigram range.