SuFEx-Based Polysulfonate Formation from Ethenesulfonyl Fluoride-Amine Adducts

Organocatalytic SuFEx click reactions of SO2F2

An organocatalytic method for the SuFEx click reaction of gaseous SO2F2 is described. Different organic bases such as DBU, TBD, triethylamine and Hünig's base can efficiently catalyze the SuFEx of SO2F2 with various phenols to produce aryl fluorosulfates in 61-97% yields. Under the same conditions, pyridone, pyrazolone and amines can also react with SO2F2 to afford the corresponding heteroaryl fluorosulfates or sulfamoyl fluorides in good yields. In this process, molecular sieves absorb the acidic HF efficiently, avoiding the use of stoichiometric amounts of organosilicon reagents and excess bases.

The Modular Synthesis of Sulfondiimidoyl Fluorides and their Application to Sulfondiimidamide and Sulfondiimine Synthesis

A modular synthesis of sulfondiimidoyl fluorides-the double aza-analogues of sulfonyl fluorides-allowing variation of the carbon and both nitrogen-substituents is reported. The chemistry uses readily available organometallic reagents, commercial sulfinylamines, simple electrophiles, and N-fluorobenzenesulfonimide (NFSI), as the starting materials. The reactions are broad in scope, efficient, and scalable. We show that the sulfondiimidoyl fluoride products can be combined with amines to provide sulfondiimidamides, and with organolithium reagents to provide sulfondiimines, and that reactivity in these transformations can be modulated by variation of the N-substituents.

A portal to highly valuable indole-functionalized vinyl sulfonyl fluorides and allylic sulfonyl fluorides

A practical and efficient method for the C-3 site selective alkenylation of indoles was developed for constructing novel indole-functionalized vinyl sulfonyl fluorides and indolyl allylic sulfonyl fluorides. The reaction is accomplished with exclusive regio- and stereoselectivity without using transition metal catalysts, providing novel products of great potential value in medicinal chemistry, chemical biology, and drug discovery.

Ultrafast Flow Synthesis of o-Functionalized Benzenesulfonyl Fluorides and Subsequent SuFEx Connections via Lithiated Chemistry

Herein we present a flow-based, rapid, and straightforward approach to synthesize diverse functionalized sulfonyl fluorides by harnessing an aryllithium intermediate. The aryllithium intermediate was fully utilized under optimized conditions (0.016 s, -18 °C) to afford various functionalized sulfonyl fluorides and also intramolecular SuFEx cyclization products in high yields (27-94%). Furthermore, the integrated synthesis incorporating subsequent SuFEx connections with even unstable organolithium nucleophiles facilitated one-flow molecular assembly in high yields (42-72%).

Iterative SuFEx approach for sequence-regulated oligosulfates and its extension to periodic copolymers

The synthesis of sequence-regulated oligosulfates has not yet been established due to the difficulties in precise reactivity control. In this work, we report an example of a multi-directional divergent iterative method to furnish oligosulfates based on a chain homologation approach, in which the fluorosulfate unit is regenerated. The oligosulfate sequences are determined by high resolution mass spectrometry of the hydrolyzed fragments, and polysulfate periodic copolymers are synthesized by using oligomeric bisfluorosulfates in a bi-directional fashion. The synthetic utility of this iterative ligation is demonstrated by preparing crosslinked network polymers as synthetic adhesive materials.

N-Fluorosulfonyl Guanidine: An Entry to N-Guanyl Sulfamides and Sulfamates

Here, we present the straightforward synthesis of N-fluorosulfonyl guanidine (1) from two industrial feedstocks, guanidine hydrochloride and sulfuryl fluoride (SO2F2), using SuFEx chemistry. Compound 1 exhibits excellent stability under ambient conditions and displays unique SuFEx reactivity toward amines and phenols to generate N-guanyl sulfamides and sulfamates that have rarely been accessed. Notably, water serves as an effective solvent in this process. Our protocol provides a reliable pathway for the synthesis and investigation of these novel guanidine-containing molecules.

A mild protocol for efficient preparation of functional molecules containing triazole

The construction of a class of novel triazole molecules containing sulfonyl fluoride functionalities was achieved through Cu-catalyzed click chemistry in good to excellent yields. The sulfonyl fluoride moieties were cleaved completely under base conditions to produce N-unsubstituted triazoles quantitatively, which provides a strategy to combine SuFEx click chemistry with Cu-catalyzed click chemistry ingeniously.

Radical Hydro-Fluorosulfonylation of Propargylic Alcohols via Electron Donor-Acceptor Photoactivation

A radical hydro-fluorosulfonylation of propargyl alcohols with FSO2Cl is presented based on the photoactivation of the electron donor-acceptor (EDA) complex. The reaction avoids the requirement for photocatalysts, bases, hydrogen donor reagents, any other additives, and harsh conditions, enabling the facile synthesis of various functionalized γ-hydroxy (E)-alkenylsulfonyl fluorides. These multifunctional sulfonyl fluorides can be further diversified, providing access to various privileged molecules of biological relevance.

C-SuFEx linkage of sulfonimidoyl fluorides and organotrifluoroborates

Sulfur(VI) fluoride exchange, a new type of linkage reaction, has excellent potential for application in functional molecule linkage to prepare pharmaceuticals, biomolecules, and polymers. Herein, a C-SuFEx reaction is established to achieve fast (in minutes) linkage between sulfonimidoyl fluorides and aryl/alkyl organotrifluoroborates. Potassium organotrifluoroborates are instantaneously activated via a substoichiometric amount of trimethylsilyl triflate to afford organodifluoroboranes, releasing BF3 as an activating reagent in situ. This sulfur(VI) fluoride exchange technique is capable of forming S(VI)-C(alkyl), S(VI)-C(alkenyl) and S(VI)-C(aryl) bonds, demonstrating its broad scope. Natural products and pharmaceuticals with sensitive functional groups, such as valdecoxib, celecoxib and diacetonefructose, are compatible with this protocol, allowing the formation of diverse sulfoximines.

Non-activated Esters as Reactive Handles in Direct Post-Polymerization Modification

Non-activated esters are prominently featured functional groups in polymer science, as ester functional monomers display great structural diversity and excellent compatibility with a wide range of polymerization mechanisms. Yet, their direct use as a reactive handle in post-polymerization modification has been typically avoided due to their low reactivity, which impairs the quantitative conversion typically desired in post-polymerization modification reactions. While activated ester approaches are a well-established alternative, the modification of non-activated esters remains a synthetic and economically valuable opportunity. In this review, we discuss past and recent efforts in the utilization of non-activated ester groups as a reactive handle to facilitate transesterification and aminolysis/amidation reactions, and the potential of the developed methodologies in the context of macromolecular engineering.

FSO2N3-Enabled Synthesis of Tetrazoles from Amidines and Guanidines

Herein we report the facile syntheses of tetrazoles enabled by FSO2N3 under mild conditions. FSO2N3 has been shown as the most powerful diazotizing reagent, which converts thousands of primary amines to azides fast and orthogonally. As the follow-up studies of the diazo transfer reaction using FSO2N3, we discover that amidines and guanidines are rapidly transformed into tetrazole derivatives when reacting with FSO2N3 under an aqueous environment, which is unprecedented for tetrazole synthesis.

Sulfur-fluoride exchange (SuFEx)-enabled lead discovery of AChE inhibitors by fragment linking strategies

SuFEx click chemistry has been a method for the rapid synthesis of functional molecules with desirable properties. Here, we demonstrated a workflow that allows for in situ synthesis of sulfonamide inhibitors based on SuFEx reaction for high-throughput testing of their cholinesterase activity. According to fragment-based drug discovery (FBDD), sulfonyl fluorides [R-SO₂F] with moderate activity were identified as fragment hits, rapidly diversified into 102 analogs in SuFEx reactions, and the sulfonamides were directly screened to yield drug-like inhibitors with 70-fold higher potency (IC₅₀ = 94 nM). Moreover, the improved molecule J8-A34 can ameliorate cognitive function in Aβ_1-42-induced mouse model. Since this SuFEx linkage reaction succeeds on picomole scale for direct screening, this methodology can accelerate the development of robust biological probes and drug candidates.

Discovery of (E)-2-Methoxyethene-1-sulfonyl Fluoride for the Construction of Enaminyl Sulfonyl Fluoride

A new sulfonyl fluoride reagent (E)-2-methoxyethene-1-sulfonyl fluoride (MeO-ESF) was developed and successfully applied for the construction of enaminyl sulfonyl fluoride (N-ESF). This protocol provides highly atom-economical access to diverse N-ESF and produces CH₃OH as the sole byproduct under mild and environmentally benign conditions.

EnT-Mediated N-S Bond Homolysis of a Bifunctional Reagent Leading to Aliphatic Sulfonyl Fluorides

Sulfur(VI) fluoride exchange (SuFEx) gives rise to a plethora of high-valent sulfur linkages; however, the availability of (aliphatic) sulfonyl fluoride manifolds lag behind, owing to the limited sources of introducing the SO₂F moiety via a classical two-electron approach. Recently, radical-based methodologies have emerged as a complementary strategy to increase the diversity of accessible click partners. In this work, synthesis of a bench-stable sulfamoyl fluoride reagent is presented, which may undergo sigma-bond homolysis upon visible-light-induced sensitization to form protected β-amino sulfonyl fluorides from alkene feedstocks. Notably, this offers an appealing strategy to access various building blocks for peptido sulfonyl fluorides, relevant in a medicinal chemistry context, as well as an intriguing entry to β-ammonium sulfonates and β-sultams, from alkenes. Densely functionalized 1,3-sultones were obtained by employing allyl alcohols as substrates. Surprisingly, allyl chloride-derived β-imino sulfonyl fluoride underwent S-O bond formation and ring closure to yield rigid cyclopropyl β-imino sulfonate ester under SuFEx conditions. Furthermore, by engaging a thiol-based hydrogen atom donor in the reaction, the reactivity of the same reagent can be tuned toward the direct synthesis of aliphatic sulfonyl fluorides. Mechanistic experiments indicate an energy transfer (EnT)-mediated process. The transient sulfonyl fluoride radical adds to the alkene and product formation occurs upon either radical-radical coupling or hydrogen atom transfer (HAT), respectively.

Accelerated and Concerted Aza-Michael Addition and SuFEx Reaction in Microdroplets in Unitary and High-Throughput Formats

The sulfur fluoride exchange (SuFEx) reaction is significant in drug discovery, materials science, and chemical biology. Conventionally, it involves installation of SO₂ F followed by fluoride exchange by a catalyst. We report catalyst-free Aza-Michael addition to install SO₂ F and then SuFEx reaction with amines, both occurring in concert, in microdroplets under ambient conditions. The microdroplet reaction is accelerated by a factor of ∼10⁴ relative to the corresponding bulk reaction. We suggest that the superacidic microdroplet surface assists SuFEx reaction by protonating fluorine to create a good leaving group. The reaction scope was established by performing individual reactions in microdroplets of 18 amines in four solvents and confirmed using high-throughput desorption electrospray ionization experiments. The study demonstrates the value of microdroplet-assisted accelerated reactions in combination with high-throughput experimentation for characterization of reaction scope.

A reductive dehalogenative process for chemo- and stereoselective synthesis of 1,3-dienylsulfonyl fluorides

A method for the mild and efficient synthesis of 1,3-dienylsulfonyl fluorides was developed via dehalogenation of α-halo-1,3-dienylsulfonyl fluorides in the presence of zinc powder and acetic acid, achieving exclusive chemo- and stereoselectivities. This protocol was successfully applied to the synthesis of heterocyclic dienylsulfonyl fluorides and polyene sulfonyl fluoride.

Sulfur-Phenolate Exchange: SuFEx-Derived Dynamic Covalent Reactions and Degradation of SuFEx Polymers

The products of the SuFEx reaction between sulfonimidoyl fluorides and phenols, sulfonimidates, are shown to display dynamic covalent chemistry with other phenols. This reaction was shown to be enantiospecific, finished in minutes at room temperature in high yields, and useful for both asymmetric synthesis and sustainable polymer production. Its wide scope further extends the usefulness of SuFEx and related click chemistries.

Synthesis and 18F Labeling of Alkenyl Sulfonyl Fluorides via an Unconventional Elimination Pathway

A successful Cu-catalyzed addition of both Cl and SO₂OCF₂H groups into alkenes allows us to discover the unusual reactivity of the SO₂OCF₂H group. As opposed to common sulfonic esters (RSO₂-O-R'), in which the R' group is highly electrophilic, the SO₂ moiety demonstrates higher electrophilicity in RSO₂-OCF₂H. The unexpected reactivity is further developed not only as a synthetic tool for well-functionalized alkenyl sulfonyl fluorides but also for the first ¹⁸F labeling of alkenyl sulfonyl fluorides.

A regio- and stereoselective Heck-Matsuda process for construction of γ-aryl allylsulfonyl fluorides

A highly efficient regio- and stereoselective Heck–Matsuda method was developed employing aryl diazoniums and allylsulfonyl fluorides for the construction of a class of novel γ-aryl allylsulfonyl fluorides in the presence of Pd(OAc)₂ and PPh₃. The method features excellent regio- and stereoselectivity (up to 100% E-selectivity), broad substrate scope and mild reaction conditions. Further application of γ-aryl allylsulfonyl fluoride in SuFEx reactions was achieved to provide their corresponding sulfonates and sulfonamides in excellent yields.

A Heck–Matsuda reaction of aryl diazoniums with allylsulfonyl fluorides for the construction of γ-aryl allylsulfonyl fluorides was developed.

Introducing SuFEx click chemistry into aliphatic polycarbonates: a novel toolbox/platform for post-modification as biomaterials

As a biodegradable and biocompatible biomaterial, aliphatic polycarbonates (APCs) have attracted substantial attention in terms of post-polymerization modification (PPM) for functionalization. A strategy for the introduction of sulfur(VI)-fluoride exchange (SuFEx) click chemistry into APCs for PPM is proposed for the first time in this work. 4'-(Fluorosulfonyl)benzyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate (FMC) was designed as a SuFEx clickable cyclic carbonate for APCs via ring-opening polymerization (ROP), and an operational and nontoxic synthetic route was achieved. FMC managed to undergo both ROP and PPM through the SuFEx click chemistry organocatalytically without constraining or antagonizing each other, using 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) as a co-organocatalyst here. Its ROP was systematically investigated, and density functional theory (DFT) calculations were performed to understand the acid-base catalytic mechanism in the anionic ROP. Exploratory investigations into PPM by SuFEx of poly(FMC) were conducted as biomaterials, and the one-pot strategies to achieve both ROP and SuFEx were confirmed.

A practical fluorosulfonylating platform via photocatalytic imidazolium-based SO2F radical reagent

Sulfonyl fluorides are key components in the fields of chemical biology, materials science and drug discovery. In this line, the highly active SO₂F radical has been employed for the construction of sulfonyl fluorides, but the utilization of gaseous ClSO₂F as radical precursor is limited due to the tedious and hazardous preparation. Meanwhile, the synthesis of sulfonyl fluorides from inert SO₂F₂ gas through a fluorosulfonyl radical (·SO₂F) process has met with inevitable difficulties due to the high homolytic bond dissociation energy of the S(VI)-F bond. Here we report a radical fluorosulfonylation strategy for the stereoselective synthesis of alkenyl sulfonyl fluorides and functional alkyl sulfonyl fluorides with an air-stable crystalline benzimidazolium fluorosulfonate cationic salt reagent. This bench-stable redox-active reagent offers a useful and operational protocol for the radical fluorosulfonylation of unsaturated hydrocarbons with good yield and high stereoselectivity, which can be further transformed into valuable functional SO₂F moieties.

Sulfonyl fluorides have potential application in chemical biology, materials science, and drug discovery, but their preparation remains challenging. Here, the authors report an air-stable fluorosulfonylating reagent that enables the radical fluorosulfonylation, hydrofluorosulfonylation and migratory SO₂F-difunctionalization of unsaturated hydrocarbons to construct a variety of sulfonyl fluoride compounds.

Regioselective conjugate addition of isoxazol-5-ones to ethenesulfonyl fluoride

The highly regioselective conjugate addition of isoxazol-5-ones to ethenesulfonyl fluoride (ESF) has been developed. In the presence of different bases, N2-alkylated and C4-alkylated isoxazol-5-ones with a sulfonyl fluoride group were obtained separately with good to excellent yields. Further transformations with amines and phenol gave sulfonamides and sulfonates. The intriguing combination of isoxazol-5-ones and the sulfonyl fluoride group produces valuable products for drug discovery.

Photoredox catalytic radical fluorosulfonylation of olefins enabled by a bench-stable redox-active fluorosulfonyl radical precursor

Sulfonyl fluorides have attracted considerable and growing research interests from various disciplines, which raises a high demand for novel and effective methods to access this class of compounds. Radical flurosulfonylation is recently emerging as a promising approach for the synthesis of sulfonyl fluorides. However, the scope of applicable substrate and reaction types are severely restricted by limited known radical reagents. Here, we introduce a solid state, redox-active type of fluorosulfonyl radical reagents, 1-fluorosulfonyl 2-aryl benzoimidazolium triflate (FABI) salts, which enable the radical fluorosulfonylation of olefins under photoredox conditions. In comparison with the known radical precursor, gaseous FSO2Cl, FABI salts are bench-stable, easy to handle, affording high yields in the radical fluorosulfonylation of olefins with before challenging substrates. The advantage of FABIs is further demonstrated in the development of an alkoxyl-fluorosulfonyl difunctionalization reaction of olefins, which forges a facile access to useful β-alkoxyl sulfonyl fluorides and related compounds, and would thus benefit the related study in the context of chemical biology and drug discovery in the future.

A cascade reaction for regioselective construction of pyrazole-containing aliphatic sulfonyl fluorides

A copper-catalyzed cascade reaction of α-diazocarbonyl compounds with ethenesulfonyl fluoride (ESF) is developed, affording a variety of highly functionalized pyrazolyl aliphatic sulfonyl fluorides in good to excellent yields (66-98%). This transformation features broad substrates, exclusive regioselectivity, high atom economy and operational simplicity, thus providing a straightforward method for the direct construction of pyrazole-containing aliphatic sulfonyl fluorides, which will provide great applicable value in medicinal chemistry and other related disciplines.

Radical 1-Fluorosulfonyl-2-alkynylation of Unactivated Alkenes

Sulfonyl fluorides have found widespread use in chemical biology and drug discovery. The development of synthetic methods for the introduction of the sulfonyl fluoride moiety is therefore of importance. Herein, a transition-metal-free radical 1,2-difunctionalization of unactivated alkenes via FSO2 -radical addition with subsequent vicinal alkynylation to access β-alkynyl-fluorosulfonylalkanes is presented. Alkynyl sulfonyl fluorides are introduced as highly valuable bifunctional radical trapping reagents that also serve as FSO2 -radical precursors. The β-alkynyl-fluorosulfonylalkanes obtained in these transformations can be readily diversified by using SuFEx click chemistry to obtain sulfonates and sulfonamides.

SuFEx-enabled, chemoselective synthesis of triflates, triflamides and triflimidates

Sulfur(vi) Fluoride Exchange (SuFEx) chemistry has emerged as a next-generation click reaction, designed to assemble functional molecules quickly and modularly. Here, we report the ex situ generation of trifluoromethanesulfonyl fluoride (CF3SO2F) gas in a two chamber system, and its use as a new SuFEx handle to efficiently synthesize triflates and triflamides. This broadly tolerated protocol lends itself to peptide modification or to telescoping into coupling reactions. Moreover, redesigning the SVI-F connector with a S[double bond, length as m-dash]O → S[double bond, length as m-dash]NR replacement furnished the analogous triflimidoyl fluorides as SuFEx electrophiles, which were engaged in the synthesis of rarely reported triflimidate esters. Notably, experiments showed H2O to be the key towards achieving chemoselective trifluoromethanesulfonation of phenols vs. amine groups, a phenomenon best explained-using ab initio metadynamics simulations-by a hydrogen bonded termolecular transition state for the CF3SO2F triflylation of amines.

Configurationally Chiral SuFEx-Based Polymers

Novel methods to make synthetic chiral polymers are highly desirable given their potential in a rapidly increasing number of bio-inspired applications. The enantiospecific sulfur-fluorine exchange (SuFEx) reaction of chiral di-sulfonimidoyl fluorides (di-SFs) with diphenols, was used to produce high-molecular-weight chiral polymers with configurational backbone chirality. The resulting new class of polymers, polysulfonimidates, can be efficiently produced via this step-growth mechanism for a wide range of di-SFs and diphenols, yielding MnPS up to 283 kDa with a typical dispersity Đ around 1.6. The optical activity of the resulting chiral polymers is largely due to the intrinsic asymmetry of the S atoms (configurational chirality). Finally, the enantiospecificity (ee>98 %) of the polymerization reaction was demonstrated by the degradation of a disulfide-containing polysulfonimidate. This novel route towards configurational main-chain chirality opens up new approaches towards tailor-made chiral polymers with precisely defined properties.

Sulfonyl fluorides as targets and substrates in the development of new synthetic methods

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. Among these, sulfonyl fluorides have emerged as the workhorse 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 proved 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.

Electrochemical Synthesis of Sulfonyl Fluorides from Sulfonyl Hydrazides

The synthesis of sulfonyl fluorides via the reaction of sulfonyl hydrazides and Et3N3HF under electrochemical conditions is reported. Various sulfonyl fluorides were obtained in good yields under a constant current...

Modular synthesis of triazoles from 2-azidoacrylamides having a nucleophilic amino group

Assembling methods using 2-azidoacrylamides having a nucleophilic amino group are disclosed. Divergent transformations of the amine-type trivalent platform were accomplished with a wide variety of electrophiles to provide a broad...

Copper-catalyzed three-component reaction of arylhydrazine hydrochloride, DABSO, and NFSI for the synthesis of arenesulfonyl fluorides

This paper reports a convenient copper-catalyzed three-component conversion of arylhydrazine hydrochlorides to arenesulfonyl fluorides in good yields under mild conditions, using 1,4-diazabicyclo [2.2.2]octane bis(sulfur dioxide) (DABSO) as a sulfonyl source and N-fluorobenzenesulfonimide (NFSI) as a fluorine source based on a radical sulfur dioxide insertion and fluorination strategy. Notably, arylhydrazine hydrochloride is used as a safe precursor of aryl radicals.

Copper-Promoted Conjugate Addition of Carboxylic Acids to Ethenesulfonyl Fluoride (ESF) for Constructing Aliphatic Sulfonyl Fluorides

A CuO-promoted direct hydrocarboxylation of ethenesulfonyl fluoride (ESF) was developed using carboxylic acid as a nucleophile under mild conditions. A variety of molecules containing both ester group and aliphatic sulfonyl fluoride moiety exhibit great potential in medicinal chemistry and chemical biology. Furthermore, the modification of the known drugs Ibuprofen and Aspirin was also demonstrated.

SuFEx-Click Approach for the Synthesis of Soluble Polymer-Bound MacMillan Catalysts for the Asymmetric Diels–Alder Reaction

Novel polymeric MacMillan catalysts were prepared from modified chiral imidazolidin-4-one monomers via sulfur(VI) fluoride exchange chemistry. The resulting polysulfates containing chiral imidazolidin-4-one units could be employed as polymeric organocatalysts for the asymmetric Diels–Alder reaction. With the use of these polysulfate catalysts, sufficient catalytic activity and enantioselectivity were obtained, which were similar to those obtained by monomeric catalysts in a homogeneous catalytic reaction. In addition, the polysulfate catalysts could be recovered and reused five times without a considerable loss of activity and selectivity.

SuFExable polymers with helical structures derived from thionyl tetrafluoride

Sulfur(VI) fluoride exchange (SuFEx) is a category of click chemistry that enables covalent linking of modular units through sulfur(VI) connective hubs. The efficiency of SuFEx and the stability of the resulting bonds have led to polymer chemistry applications. Now, we report the SuFEx click chemistry synthesis of several structurally diverse SOF₄-derived copolymers based on the polymerization of bis(iminosulfur oxydifluorides) and bis(aryl silyl ethers). This polymer class presents two key characteristics. First, the [-N=S(=O)F-O-] polymer backbone linkages are themselves SuFExable and undergo precise SuFEx-based post-modification with phenols or amines to yield branched functional polymers. Second, studies of individual polymer chains of several of these new materials indicate helical polymer structures. The robust nature of SuFEx click chemistry offers the potential for post-polymerization modification, enabling the synthesis of materials with control over composition and conformation.

Photoredox-catalyzed aminofluorosulfonylation of unactivated olefins

The development of efficient approaches to access sulfonyl fluorides is of great significance because of the widespread applications of these structural motifs in many areas, among which the emerging sulfur(vi) fluoride exchange (SuFEx) click chemistry is the most prominent. Here, we report the first three-component aminofluorosulfonylation of unactivated olefins by merging photoredox-catalyzed proton-coupled electron transfer (PCET) activation with radical relay processes. Various aliphatic sulfonyl fluorides featuring a privileged 5-membered heterocyclic core have been efficiently afforded under mild conditions with good functional group tolerance. The synthetic potential of the sulfonyl fluoride products has been examined by diverse transformations including SuFEx reactions and transition metal-catalyzed cross-coupling reactions. Mechanistic studies demonstrate that amidyl radicals, alkyl radicals and sulfonyl radicals are involved in this difunctionalization transformation.

Identification of simple arylfluorosulfates as potent agents against resistant bacteria

Sulfur fluoride exchange (SuFEx), a next generation of click chemistry, opens an avenue for drug discovery. We report here the discovery and structure-activity relationship studies of a series of arylfluorosulfates, synthesized via SuFEx, as antibacterial agents. Arylfluorosulfates 3, 81, and 101 showed potency to overcome multidrug resistance and were not susceptible to the generation of resistance. They exhibited rapid bactericidal potency and selectively killed gram-positive bacterial strains. These compounds also exhibited the ability to disrupt established bacterial biofilm and kill persisters derived from biofilm. Furthermore, arylfluorosulfate 3 had a synergistic effect with streptomycin and gentamicin. In addition, their anti-MRSA potency was evaluated and determined by the Caenorhabditis elegans model.