Generation of N-aminosulfonamides via a photo-induced fixation of sulfur dioxide into aryl/alkyl halides

Abstract

A catalyst-free aminosulfonylation through insertion of sulfur dioxide with aryl/alkyl halides enabled by photoenergy is presented. Under ultraviolet irradiation, a three-component reaction of aryl/alkyl halides, sulfur dioxide, and hydrazines proceeds under mild conditions without any metals or photo-redox catalysts.

Radicals and Sulfur Dioxide: A Versatile Combination for the Construction of Sulfonyl‐Containing Molecules

“…Later on, several groups reported analogous methods employing differentr adical precursors (Scheme 20). [53] The Wu group developed ac atalyst-free aminosulfonylation of aryl or alkyl halides (60)w ith hydrazines (53)a nd DABCO·2SO 2 in the presence of tetrabutylammonium iodide (TBAI) (Scheme 20 i).…”

“…[53c] Diaryliodonium salts (64) serve as radicalp recursors in this case and sulfur dioxide is generated in situ by acid-mediated decomposition of bisulfite salts. Han and Pan developeda no xidative coupling of two types of hydrazines (65)a nd (53)w ith potassium metabisulfite as as ulfur dioxide surrogate (Scheme20iv). This transformation displays ar emarkably degree of chemoselectivity.…”

“…Later on, several groups reported analogous methods employing different radical precursors (Scheme ) . The Wu group developed a catalyst‐free aminosulfonylation of aryl or alkyl halides ( 60 ) with hydrazines ( 53 ) and DABCO ⋅ 2 SO 2 in the presence of tetrabutylammonium iodide (TBAI) (Scheme i ) . Irradiation with ultraviolet light (mercury lamp) is used for generation of carbon‐centered radicals by homolysis of the carbon‐halogen bond.…”

Photoredox‐Catalyzed Functionalization of Alkenes with Thiourea Dioxide: Construction of Alkyl Sulfones or Sulfonamides

“…In the meantime, the combination of aryl/alkyl radicals and sulfur dioxide was discovered to provide a green and efficient way to generate sulfonyl radicals, avoiding the use of sulfonyl precursors . During the process, different radical precursors, including aryldiazonium tetrafluoroborates, aryl/alkyl halides, diaryliodonium salts and others could be reduced to generate aryl radicals, which would capture the sulfur dioxide released from DABCO·(SO 2 ) 2 or inorganic sulfites leading to aryl/alkyl sulfonyl radical intermediates. Therefore, diverse sulfonyl compounds could be prepared efficiently and environmentally friendly with the insertion of sulfur dioxide, particularly from the low‐cost inorganic sulfites.…”

Recent developments for the photoinduced Ar–X bond dissociation reaction

“…51 This aminosulfonylation process through the insertion of sulfur dioxide under ultraviolet irradiation, proceeded at room temperature without any metals or photo-redox catalysts, leading to the corresponding N-aminosulfonamides in good to excellent yields. 51 This aminosulfonylation process through the insertion of sulfur dioxide under ultraviolet irradiation, proceeded at room temperature without any metals or photo-redox catalysts, leading to the corresponding N-aminosulfonamides in good to excellent yields.…”