<i>N</i>‑Radical Initiated Aminosulfonylation of Unactivated C(sp³)–H Bond through Insertion of Sulfur Dioxide

<i>N</i>-Radical initiated aminosulfonylation of unactivated C­(sp³)–H bond through insertion of sulfur dioxide in the presence of visible light is reported. <i>O</i>-Aryl oximes react with DABCO·(SO₂)₂ smoothly at room temperature under blue LED irradiation without any metals or photoredox catalysts, generating diverse 5,6-dihydro-4<i>H</i>-1,2-thiazine 1,1-dioxides in good yield. Additionally, this approach can be extended to the synthesis of 1<i>H</i>-benzo­[<i>d</i>]­[1,2]­thiazine 2,2-dioxides. During the reaction process, an <i>N</i>-radical is initiated by the treatment of <i>O</i>-aryl oximes with DABCO·(SO₂)₂ under visible-light irradiation. It is followed by aminosulfonylation of a nearby C­(sp³)–H bond through 1,5-hydrogen atom transfer with accompanying insertion of sulfur dioxide to provide 1,2-thiazine 1,1-dioxide derivatives