A Route to O‐Aminosulfonates and Sulfonamides through Insertion of Sulfur Dioxide and Hydrogen Atom Transfer

Abstract A three‐component reaction of aryldiazonium tetrafluoroborates, the 1,4‐diazabicyclo[2.2.2]octane⋅bis(sulfur dioxide) adduct [DABCO⋅(SO 2 ) 2 ] and hydroxylamines under catalyst‐free and additive‐free conditions has been developed, providing aryl O ‐aminosulfonates in good yields. Sulfonamides could also be obtained via a one‐pot process through the reaction of aryldiazonium tetrafluoroborates, DABCO⋅(SO 2 ) 2 and amines in the presence of N ‐hydroxybenzotriazole. A mechanism involving the insertion of sulfur dioxide and hydrogen atom transfer is proposed and supported by theoretical calculations. magnified image