Synthesis of Aromatic Sulfonamides through a Copper-Catalyzed Coupling of Aryldiazonium Tetrafluoroborates, DABCO·(SO₂)₂, and N-Chloroamines

Abstract

A copper-catalyzed aminosulfonylation of aryldiazonium tetrafluoroborates, DABCO·(SO), and N-chloroamines is described. This coupling reaction provides an efficient and simple approach to a wide range of sulfonamides in moderate to good yields under mild conditions. Mechanistic investigation suggests that a radical process and transition-metal catalysis are merged in this tandem reaction.

A new outlook in oxidative transformations and coupling reactions via in situ generation of organic chloramines

“…Luca developed a new direct methodology for the conversion of aldehydes to amides (Scheme 2e) [ 28 ] in the presence of iron(III) chloride, with N ‐chloramines as a nitrogen‐centered radical precursor, for the construction of amide bond. Wu introduced transition‐metal‐catalyzed aminosulfonylation reaction (Scheme 2f) [ 29 ] with N ‐chloramine as the amino source during sulfur dioxide insertion, for the construction of the S–N bond.…”

“…[ 27 ] (e) Amidation(C=O)N bond using N ‐chloramines. [ 28 ] (f) S–N bond formation using N ‐chloramines [ 29 ]…”

S(vi) in three-component sulfonamide synthesis: use of sulfuric chloride as a linchpin in palladium-catalyzed Suzuki–Miyaura coupling

“…Extra oxidants and harsh conditions were usually used, and some of the transformations required "oxidative" substrates, such as nitroarenes and chloroamines. 14 Early in 2020, a reductive hydrosulfonamination of alkenes by sulfamoyl chlorides was reported, 15 which gave us the inspiration to use in situ generated sulfamoyl chlorides as the electrophile for the synthesis of aryl sulfonamides by Suzuki-Miyaura coupling. In this way, sulfamoyl chlorides could be formed by nucleophilic substitution of an amine to sulfuric chloride, and the S(VI) central atom introduced into the reaction could reverse the electronic properties of the amine, which would eliminate the addition of oxidants (Scheme 1c).…”

“…Extra oxidants and harsh conditions were usually used, and some of the transformations required “oxidative” substrates, such as nitroarenes and chloroamines. 14 …”

Selective Late‐Stage Sulfonyl Chloride Formation from Sulfonamides Enabled by Pyry‐BF4

“…[3] For this reason, intense efforts have been focused on developing efficient strategies for their synthesis, and a plethora of methods have appeared in the literature. [4] However, a closer analysis of these precedents reveals that primary sulfonamide moiety has always been conceived as an endgame point, rather than a modifiable handle for derivatization. Based on the importance of sulfurcontaining motifs for drug discovery and their large presence in many medicinal chemistry libraries, [2] we envisaged that primary sulfonamides could be repurposed as powerful coupling partners in drug discovery if methods to convert the NH 2 into other functionalities would exist.…”