A Sequence-Controlled Di-Functionalization of an SO2-Surrogate with Amines for the Synthesis of Sulfonamides

A streamlined one-pot, sequence-controlled di-functionalization strategy has been developed for the synthesis of structurally diverse sulfonamides under mild conditions. The reaction utilizes DABCO•(SO₂)₂ as an SO₂-surrogate and engages two amines—either identical or different—in a stepwise manner. Potassium iodide (KI) acts as a stoichiometric reductant, while isoamyl nitrite facilitates the in situ generation of reactive intermediates under a nitrogen atmosphere in acetonitrile at room temperature. The transformation proceeds via a sulfinamide intermediate, enabling the efficient construction of sulfonamides with broad substrate scope, high functional group tolerance, and excellent yields. The method features clean reaction profiles, operational simplicity, and scalability, making it a practical and mechanistically informed approach to sulfonamide synthesis.