The advent of sulfur(VI)-fluoride exchange (SuFEx) processes as transformations with click-like reactivity has invigorated research into electrophilic species featuring a sulfur-fluorine bond. Amongst these, sulfonyl fluorides have emerged as the work-horse functional group, with diverse applications being reported. Sulfonyl fluorides are used as electrophilic warheads by both medicinal chemists and chemical biologists. The balance of reactivity and stability that is so attractive for these applications, particularly the resistance of sulfonyl fluorides to hydrolysis under physiological conditions, has provided opportunities for synthetic chemists. New synthetic approaches that start with sulfur-containing substrates include the activation of sulfonamides using pyrilium salts, the deoxygenation of sulfonic acids, and the electrochemical oxidation of thiols. Employing non-sulfur containing substrates has led to the development of transition-metal-catalysed processes based on palladium, copper and nickel, as well as the use of SO2F2 gas as an electrophilic hub. Selectively manipulating molecules that already contain a sulfonyl fluoride group has also proven to be a popular tactic, with metal-catalysed processes again at the fore. Finally, coaxing sulfonyl fluorides to engage with nucleophiles, when required, and under suitable reaction conditions, has led to new activation methods. This review provides an overview of the challenges in the efficient synthesis and manipulation of these intriguing functional groups.
A series of low‐molecular‐weight, compact, and multifunctional cyclic alkenylsulfonyl fluorides were efficiently prepared from the corresponding alkenyl triflates. Palladium‐catalyzed sulfur dioxide insertion using the surrogate reagent DABSO effects sulfinate formation, before trapping with an F electrophile delivers the sulfonyl fluorides. A broad range of functional groups are tolerated, and a correspondingly large collection of derivatization reactions are possible on the products, including substitution at sulfur, conjugate addition, and N‐functionalization. Together, these attributes suggest that this method could find new applications in chemical biology.
Simple access to aryl sulfinates from aryl iodides and bromides is reported using an inexpensive Ni‐electrocatalytic protocol. The reaction exhibits a broad scope, uses stock solution of simple SO2 as sulfur source, and can be scaled up in batch and recycle flow settings. The limitations of this reaction are clearly shown and put into context by benchmarking with state‐of‐the‐art Pd‐based methods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.