Metal‐Free Aminosulfonylation of Aryldiazonium Tetrafluoroborates with DABCO⋅(SO₂)₂ and Hydrazines

Abstract

The coupling of aryldiazonium tetrafluoroborates, DABCO⋅(SO2)2, and hydrazines under metal-free conditions leads to the formation of aryl N-aminosulfonamides. The reaction proceeds smoothly at room temperature and shows broad functional-group tolerance. A radical process is proposed for this transformation.

tert‐Butyl Nitrite (TBN), a Multitasking Reagent in Organic Synthesis

“…In this methodology, DABSO act as SO 2 surrogate.T he radical scavenger TEMPO experiment shows that the phenyl radical was produced under the present reactionc onditions and both DABSO and hydrazine are vital in the introduction of the phenylr adical. [50] In 2014, Wu group again reported ao ne-pot strategy where aromatic amines (33)w ere utilized in the SO 2 insertion reaction instead of aryl diazonium salts(Scheme 24). [51] In 2002, Andrus's group disclosed aP d-imidazolium carbene catalyzed Mizoroki-Heck coupling of the in situ generated aryl diazonium salts using TBN.…”

Vicinal Difluoroalkylation and Aminosulfonylation of Alkynes under Photoinduced Conditions

“…The incorporation of sulfur dioxide through a radical mechanism for the generation of sulfonyl compounds was developed . For example, N ‐aminosulfonamides could be obtained through a radical coupling of aryldiazonium salts, DABCO⋅(SO 2 ) 2 (DABCO=1,4‐diazabicyclo[2.2.2]octane), and hydrazines . This bench‐stable sulfur dioxide surrogate could be further applied in the radical reaction of aryldiazonium salts with aryl propiolates, leading to the formation of 3‐sulfonated coumarins .…”

Bacterial Synthesis of Unusual Sulfonamide and Sulfone Antibiotics by Flavoenzyme‐Mediated Sulfur Dioxide Capture

“…[15] Further support for ap roposed radical mechanism comes from recent synthetic studies towards aryl N-aminosulfonamides,where sulfur dioxide was inserted into small molecules by ar adical process. [16] …”