Aqueous Process Chemistry: The Preparation of Aryl Sulfonyl Chlorides

Abstract

The use of aqueous acidic conditions for the preparation of arylsulfonyl chlorides from diazonium salts in the presence of copper salts, preferably CuCl, together with thionyl chloride as the sulfur dioxide source, has considerable advantages over recommended literature procedures, whereby reactions are carried out in acetic acid with minimisation of water content of the solvent. The method has been shown to be successful for a wide range of electron-deficient and electron-neutral aryl substrates. The sulfonyl chlorides are protected from hydrolysis by their low solubility in water, which results in their direct precipitation from the reaction mixture in good yields (>70%) and high strength (>98% w/w). The aqueous process, which is additionally safer and more robust, can be readily scaled up and has significant environmental benefits.

Retraction of “Ascorbic Acid-Promoted C–H Arylation of Heterocyclic N-Oxides through in Situ Diazotisation of Anilines: A Green and Selective Coupling Process”

“…Along with problems arising due to the high reactivity of the aryl radical intermediates, an additional challenge is the handling of the potentially unstable aryl diazonium precursors. Although these high energy species are routinely handled on large scale, [29][30][31][32] safety concerns 33 still inhibit their adoption among the wider synthetic community.…”

Trifluormethylchlorsulfonylierung von Alkenen – Hinweise auf einen Innensphärenmechanismus eines Kupferphenanthrolin‐Photoredoxkatalysators

“…Der markante Unterschied zwischen [Cu(dap) 2 ]Cl und Ruthenium‐, Iridium‐ oder Eosin‐Y‐Katalysatoren deutet auf eine für den hier berichteten Gesamtprozess essentielle Rolle des Kupfers hin. Vermutlich wird SO 2 Cl16, 17 koordiniert und stellt es so als reaktives Intermediat zur Verfügung. Die Quantenausbeute dieses Prozesses wurde mit 12 % bestimmt, was einen Radikalkettenmechanismus ausschließt.…”

The Development and Application of Sulfur Dioxide Surrogates in Synthetic Organic Chemistry

“…[31] This method of SO 2 generation occurs via a rapid and exothermic reaction, which together with the potential incompatibility of both the byproduct, HCl, and original SOCl 2 , suggests why this appears to be a relatively littleused procedure. It is, however, perfectly suited for the aqueous hydrochloric acid conditions required for Sandmeyer chemistry.…”