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

A three-component reaction of aryldiazonium tetrafluoroborates, the 1,4-diazabicyclo[2.2.2]octane center dot bis(sulfur dioxide) adduct [DABCO center dot(SO2)(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 center dot(SO2)(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.