Recent advances in the radical-mediated decyanative alkylation of cyano(hetero)arene

Photocatalytic Consecutive Photoinduced Electron Transfer-Enabled C(sp3)-H Pyridylation of Dihydroquinoxalin-2-ones

A photocatalytic decyanative C(sp3)-H pyridination of dihydroquinoxalin-2-ones with 4-cyanopyridines was developed by utilizing 4CzIPN as the photocatalyst. Mechanism studies show that this organophotocatalytic direct C(sp3)-H pyridination undergoes a radical-radical cross-coupling pathway promoted by consecutive photoinduced electron transfer.

Chemoselective Dehydrogenation and Hetero-Arylation of Amides via Radical Translocation Enabled by Photoexcited Triplet Ketone Catalysis

We herein report the chemoselective dehydrogenation and heteroarylation of amides through photoexcited triplet ketone catalysis. Under mild reaction conditions, the generated aryl radical through the halogen atom transfer (XAT) process further undergoes an intramolecular 1,5-HAT event to generate an α-amido alkyl radical, which then intercepted with either cobalt or a reduced cyano arene radical leads to dehydrogenated and heteroarylated products, respectively, in good yields.

Organophotocatalytic pyridination of N-arylglycines with 4-cyanopyridines by decarboxylative and decyanative radical-radical coupling

A photocatalytic decarboxylative aminoalkylation of 4-cyanopyridines with N-arylglycines is achieved, providing 4-(aminomethyl)pyridine derivatives in moderate to good yields. This organic photocatalytic reaction undergoes a radical-radical cross-coupling process under redox-neutral conditions, featuring simple operation, readily available N-arylglycines and a broad substrate scope. Mechanistic investigations indicated that a proton-coupled electron-transfer process was involved to enable the single electron transfer between the reduced photocatalyst and 4-cyanopyridine in the presence of N-arylglycines.

Photoinduced, Redox-Neutral Decyanative and Defluorinative Phosphination of (Hetero)Arenes

Triarylphosphines play a crucial role in organic synthesis as versatile components serving as ligands, catalysts, and reactants. This study introduces a metal-free, visible-light-induced method for the cross-coupling of cyanopyridines or polyfluoroarenes with diarylphosphines. This approach facilitates the formation of C(sp2)-P bonds through redox-neutral decyanative or defluorinative process, enabling the convenient synthesis of diverse triarylphosphines.

Synthesis of Diarylalkanes by Photoreductive 1,2-Diarylation of Alkenes with Aryl Halides and Cyanoaromatics

We report a visible light-induced photoreductive strategy for three-component diarylation of alkenes with aryl halides and cyanoaromatics. Upon photoredox catalysis and with tertiary alkyl amines as the electron transfer agent, aryl halides selectively undergo halogen atom transfer to generate the aryl radicals and two C(sp2)-C(sp3) bonds between the cabron atoms are created in a radical addition and radical-radical coupling fashion to rapidly assemble diverse functionalized polyarylalkanes with high regio- and chemoselectivity. This method can be applied to broad feedstocks, including terminal alkenes, internal alkenes, aryl iodides, aryl bromides, aryl chlorides, electron-deficient benzonitriles, and isonicotinonitriles.

Photoreductive 1,4-Dicarbofunctionalization of 1,3-Enynes with Organoiodides and Cyanoarenes via Halogen-Atom Transfer

A photoreductive halogen-atom transfer (XAT) strategy for 1,4-dicarbofunctionalization of 1,3-enynes with organoiodides and cyanoarenes is disclosed, enabling access to functionalized allenes in a highly regio-, chemo-, and stereoselective manner. Upon the photoredox catalysis and the activation of Et3N XAT agents, the mild conditions and high functional group tolerance of this protocol enable the formation of two C-C bonds, including a C(sp3)-C(sp3) bond and a C(sp2)-C(sp2) bond, in a single reaction step, and provides a general avenue to polysubstituted allenes and late-stage modification of bioactive compounds.

CdS Quantum Dot Gels as a Direct Hydrogen Atom Transfer Photocatalyst for C-H Activation

Here, we report CdS quantum dot (QD) gels, a three-dimensional network of interconnected CdS QDs, as a new type of direct hydrogen atom transfer (d-HAT) photocatalyst for C-H activation. We discovered that the photoexcited CdS QD gel could generate various neutral radicals, including α-amido, heterocyclic, acyl, and benzylic radicals, from their corresponding stable molecular substrates, including amides, thio/ethers, aldehydes, and benzylic compounds. Its C-H activation ability imparts a broad substrate and reaction scope. The mechanistic study reveals that this reactivity is intrinsic to CdS materials, and the neutral radical generation did not proceed via the conventional sequential electron transfer and proton transfer pathway. Instead, the C-H bonds are activated by the photoexcited CdS QD gel via a d-HAT mechanism. This d-HAT mechanism is supported by the linear correlation between the logarithm of the C-H bond activation rate constant and the C-H bond dissociation energy (BDE) with a Brønsted slope α=0.5. Our findings expand the currently limited direct hydrogen atom transfer photocatalysis toolbox and provide new possibilities for photocatalytic C-H activation.

α-C(sp3)-H (Hetero)Arylation of Thioethers Enabled by Photoexcited Triplet Ketone Catalysis

We report herein α-C(sp3)-H (hetero)arylation of thioethers enabled by dual nickel and photoexcited triplet ketone catalysis. The mild reaction conditions of this protocol tolerate a variety of functional groups and further facilitate the late-stage functionalization of biologically relevant molecules to afford corresponding products in moderate to good yields. Preliminary mechanistic studies suggest that the generation of the α-thioalkyl radical takes place through a hydrogen atom transfer (HAT) event, which is involved in the rate-limiting step and in the nickel cycle, the reaction of the α-thioalkyl radical with Ni(0)Ln catalyst followed by oxidative addition of aryl bromide is the dominating pathway. Furthermore, the heteroaromatic benzylic thioethers can also be achieved from the corresponding reduced 4-cyano pyridine derivatives in the presence of a ketone catalyst through a radical-radical coupling reaction without metal. The increased yield of the products in the presence of DABCO might indicate a higher rate of α-thioalkyl radical formation from thioethers through the HAT event by DABCO radical cation.

Harnessing the potential of acyl triazoles in bifunctional cobalt-catalyzed radical cross-coupling reactions

Persistent radicals facilitate numerous selective radical coupling reactions. Here, we have identified acyl triazole as a new and versatile moiety for generating persistent radical intermediates through single-electron transfer processes. The efficient generation of these persistent radicals is facilitated by the formation of substrate-coordinated cobalt complexes, which subsequently engage in radical cross-coupling reactions. Remarkably, triazole-coordinated cobalt complexes exhibit metal-hydride hydrogen atom transfer (MHAT) capabilities with alkenes, enabling the efficient synthesis of diverse ketone products without the need for external ligands. By leveraging the persistent radical effect, this catalytic approach also allows for the development of other radical cross-coupling reactions with two representative radical precursors. The discovery of acyl triazoles as effective substrates for generating persistent radicals and as ligands for cobalt catalysis, combined with the bifunctional nature of the cobalt catalytic system, opens up new avenues for the design and development of efficient and sustainable organic transformations.

Photoredox-Catalyzed Amino-Radical-Transfer-Mediated Three-Component Alkylarylation of Alkenes

We herein reported a novel photoredox-catalyzed three-component alkylarylation of vinyl arenes with alkylboronic pinacol esters (APEs) and cyanoarenes via radical addition/cross-coupling to construct 1,1-diarylalkanes. In this transformation, alkyl radicals were easily available by visible-light-induced oxidative N-H cleavage of morpholine, which used APEs as a radical precursor. Furthermore, this protocol exhibited a broad substrate scope, enabling various styrenes, APEs, and cyanoarenes, as well as bioactive molecule derivatives.

Photochemical Synthesis of Nitriles from Alcohols

Nickel-catalyzed hydrocyanation of 1,3-butadiene with hydrogen cyanide gas is the predominant method for the synthesis of adiponitrile, which is an important precursor for polymer production. However, the use of fossil-derived alkenes raises environmental concerns, and hydrogen cyanide is highly volatile and extremely toxic. Herein, we report the use of biomass-derived 1,4-butanediol, as well as other primary alcohols, for photochemical synthesis of linear and branched nitriles and dinitriles, including adiponitrile, with 1,4-dicyanobenzene as the CN source. This mild, sustainable method does not require hydrogen cyanide gas or an air- or moisture-sensitive metal catalyst and is applicable for the production of dinitriles as precursors of diamines, which have potential utility for the development of novel polyamides.

Decyanative Heteroarylations of Glycine Derivatives

Amino acids and aromatic nitrogen heterocycles are widely used in pharmaceuticals. Herein, we present an effective visible-light-driven thiobenzoic acid (TBA)-catalyzed decyanative C(sp3)-H heteroarylation of glycine derivatives. This process occurs under mild and straightforward conditions, affording a range of valuable yet challenging-to-obtain α-heteroaryl amino acid derivatives. Moreover, this organocatalytic C(sp3)-C(sp2) bond formation reaction is applicable to the late-stage modification of various short peptides.

Metal Free Functionalization of Saturated Heterocycles with Vinylarenes and Pyridine Enabled by Photocatalytic Hydrogen Atom Transfer

Saturated heterocycles are important class of structural scaffolds in small-molecule drugs, natural products, and synthetic intermediates. Here, we disclosed a metal free, mild, and scalable functionalization of saturated heterocycles using vinylarenes as a linchpin approach. Key to success of this transformation is the employing of simple and cheap benzophenone as a hydrogen atom transfer (HAT) catalyst. This operationally robust process was used for the making of diverse functionalized saturated heterocycles. Furthermore, aldehydes, alkane, and alcohol have been functionalized under the optimized conditions. The potential pharmaceutical utility of the procedure has also been demonstrated by late-stage functionalization of bioactive natural compounds and pharmaceutical molecules. Initial mechanism studies and control experiments were performed to elucidate the mechanism of the reactions.

Photoredox-Catalyzed Decarboxylative Cross-Coupling Reaction to Synthesis Unsymmetrical Diarylmethanes

The photoredox-catalyzed decarboxylative cross-coupling reaction of aryl acetic acids and aryl nitriles has been achieved under an argon atmosphere in high yields. This method provides a fast way to obtain prevalent aryl acetic acids from an abundant natural source. A tentative radical mechanism has been proposed.

Paired Electrolysis-Enabled Arylation of Quinoxalin-2(1H)-ones

The first paired electrolysis-enabled arylation of quinoxalin-2(1H)-ones was achieved using cyanoarenes as the arylation reagents. A variety of 3-arylquinoxalin-2(1H)-ones with various important functional groups were obtained in moderate to good yields under metal- and chemical oxidant-free conditions. With a pair of reductive and oxidative processes occurring among the substrates and reaction intermediates, the power consumption can be dramatically reduced.

Photocatalytic redox-neutral α-C(sp3)-H pyridination of glycine derivatives and N-arylamines with cyanopyridines

A photo-induced α-C(sp3)-H decyanative pyridination of N-arylglycine derivatives with cyanopyridines was developed. This reaction was performed under organic photocatalytic and redox-neutral conditions via a radical-radical cross-coupling process. Besides, the protocol was also suitable for the C(sp3)-H pyridination of N-aryl tetrahydroisoquinolines as well as benzylamines.

Electrochemical multicomponent [2+2+1] cascade cyclization of enaminones and primary amines towards the synthesis of 4-acylimidazoles

An electrochemical multicomponent [2+2+1] cascade cyclization of enaminones and primary amines towards the synthesis of 4-acylimidazoles has been developed. In an undivided cell, enaminones and primary amines can smoothly participate in this reaction to provide a series of 1,2-disubstituted 4-acylimidazoles at room temperature. The reaction avoids the use of both transition-metal catalysts and oxidation reagents, which makes it more sustainable and renewable.

Electrochemical-Induced C-N Bond Formation: A New Method to Synthesis (Z)-Quinazolinone Oximes Using Primary Amines and Quinazolin-4(3H)-one

A novel and highly selective electrochemical method for the synthesis of diverse quinazolinone oximes via direct electrooxidation of primary amines/C(sp2)-H functionalization of oximes has been developed. The reaction is conducted in an undivided cell under constant current conditions and is oxidant-free, open-air, and eco-friendly. Notably, the protocol shows good functional group tolerance, providing versatile quinazolinone oximes in good yields. Moreover, the mechanism is investigated through control experiments and cyclic voltammogram (CV) experiments.

Visible-Light-Induced Three-Component 1,2-Alkylpyridylation of Alkenes via a Halogen-Atom Transfer Process

Visible-light-induced three-component 1,2-alkylpyridylation of alkenes with unactivated alkyl iodides and aryl cyanides is reported via a photocatalytic halogen-atom transfer (XAT) strategy. This metal-free protocol utilizes readily available tertiary alkylamine as the terminal reductant to smoothly convert alkyl iodides into the corresponding carbon radical species. The reaction features a broad substrate scope, excellent functional group tolerance, high efficiency, and mild reaction conditions. The practicability of this methodology is further demonstrated in the late-stage difunctionalization of bioactive molecules.

Transition-Metal-Free, Reductive Csp2-Csp3 Bond Constructions via Electrochemically Induced Alkyl Radicals

Construction of the Csp2-Csp3 bond without the aid of transition metal catalysts has been achieved by coupling the electrogenerated alkyl radicals with electron deficient (hetero)arenes in an undivided cell. Simultaneous cathodic reduction of both unactivated alkyl halides and cyanobenzenes under high potential enables radical-radical cross-coupling to deliver alkylarenes in the absence of transition metals. Depending on the coupling partner, the electrogenerated alkyl radicals can also proceed the Minisci-type reaction with N-heteroarenes without redox agents.

Dehalogenative Arylation of Unactivated Alkyl Halides via Electroreduction

Herein, a facile and efficient dehalogenative arylation of unactivated alkyl halides enabled by electrochemical reductive coupling is developed, affording a series of C(sp2)-C(sp3) products in moderate to good yields. This protocol proceeds in the absence of transition metal catalysts and redox mediators. The reaction features mild conditions, broad substrate scope, and high tolerance of functional groups and is demonstrated to be applicable for gram-scale synthesis and late-stage functionalization of natural products.

New insights into the mechanism of synergetic photoredox/copper(i)-catalyzed carbocyanation of 1,3-dienes: a DFT study

This work presents a DFT-based computational study to understand the mechanism, and regio- and enantioselectivities in the synergetic photoredox/copper(i)-catalyzed carbocyanation of 1,3-dienes with alkyl redox-active esters. The calculated results show an unprecedented copper catalytic mechanism, where the reaction follows a catalytic cycle involving CuI-only catalysis, instead of a Cu(i)/Cu(ii)/Cu(iii)/Cu(i) cycle as proposed in the experimental study. Moreover, it is found that the critical step involves the reaction of the cyanocopper(i) species with an allyl cation rather than the cyanocopper(ii) species reacting with an allyl radical as proposed in the experiment, and that the photocatalyst is regenerated via single electron transfer from the allyl radical to the oxidized photocatalyst. In the newly proposed photoredox/copper(i) catalysis, the reaction consists of four stages: (i) generation of the copper(i) active catalyst, (ii) formation of an allyl radical with oxidative quenching of the photoexcited species, (iii) generation of an allylcopper complex accompanied by the regeneration of the photocatalyst, and (iv) formation of the allyl cyanide product with the regeneration of the copper(i) active catalyst. The cyanation of the allyl cation is calculated to be the regio- and enantioselectivity-determining step. The excellent regio- and stereoselectivities are attributed to the favorable CH-π interaction between the substrate and catalyst as well as the small distortion of the substrate.

Electroreduction Enables Regioselective 1,2-Diarylation of Alkenes with Two Electrophiles

Precisely introducing two similar functional groups into bulk chemical alkenes represents a formidable route to complex molecules. Especially, the selective activation of two electrophiles is in crucial demand, yet challenging for cross-electrophile-coupling. Herein, we demonstrate a redox-mediated electrolysis, in which aryl nitriles are both aryl radical precursors and redox-mediators, enables an intermolecular alkene 1,2-diarylation with a remarkable regioselectivity, thereby avoiding the involvement of transition-metal catalysts. This transformation utilizes cyanoarene radical anions for activating various aryl halides (including iodides, bromides, and even chlorides) and affords 1,2-diarylation adducts in up to 83 % yield and >20 : 1 regioselectivity with more than 80 examples, providing a feasible approach to complex bibenzyl derivatives.

Photochemical Organocatalytic Functionalization of Pyridines via Pyridinyl Radicals

We report a photochemical method for the functionalization of pyridines with radicals derived from allylic C-H bonds. Overall, two substrates undergo C-H functionalization to form a new C(sp²)-C(sp³) bond. The chemistry harnesses the unique reactivity of pyridinyl radicals, generated upon single-electron reduction of pyridinium ions, which undergo effective coupling with allylic radicals. This novel mechanism enables distinct positional selectivity for pyridine functionalization that diverges from classical Minisci chemistry. Crucial was the identification of a dithiophosphoric acid that masters three catalytic tasks, sequentially acting as a Brønsted acid for pyridine protonation, a single electron transfer (SET) reductant for pyridinium ion reduction, and a hydrogen atom abstractor for the activation of allylic C(sp³)-H bonds. The resulting pyridinyl and allylic radicals then couple with high regioselectivity.

Visible-light-promoted radical cascade alkylation/cyclization: access to alkylated indolo/benzoimidazo[2,1-a]isoquinolin-6(5H)-ones

A new protocol is herein described for the direct generation of alkylated indolo/benzoimidazo[2,1-a]isoquinolin-6(5H)-one derivatives by using Hantzsch esters as alkylation radical precursors using a photoredox/K₂S₂O₈ system. This oxidative alkylation of active alkenes involves a radical cascade cyclization process and a sequence of Hantzsch ester single electron oxidation, C-C bond cleavage, alkylation, arylation and oxidative deprotonation.

Redox-neutral and metal-free synthesis of 3-(arylmethyl)chroman-4-ones via visible-light-driven alkene acylarylation

A metal- and aldehyde-free visible-light-driven photoredox-neutral alkene acylarylation with readily available cyanoarenes is described. A variety of 3-(arylmethyl)chroman-4-ones (i.e., homoisoflavonoids) and analogs are efficiently synthesized with good functional group tolerance. This mild protocol relies on a phosphoranyl radical-mediated acyl radical-initiated cyclization and selective radical-radical coupling sequence, and is also further highlighted by subsequent derivatization to chromone and 2H-chromene as well as its application in the three-component alkene acylarylation.

Photoinduced Three-Component Carboarylation of Unactivated Alkenes with Protic C(sp3)-H Feedstocks

A general and mild strategy involving three-component carboarylation of unactivated alkenes with protic C(sp³)-H feedstocks via photoredox catalysis was reported. This catalytic system is compatible with a broad range of unactivated alkenes, cyano-substituted arenes, and diverse protic C(sp³)-H feedstocks. The synthetic value of this protocol was demonstrated by the late-stage functionalization of complex molecules and the synthesis of the antiallergies including pheniramine, chlorpheniramine, and brompheniramine.

Electrochemical Oxidative C-C Bond Cleavage of Ketones for C-N Bond Formation: A Route to Amides

Herein, we report an efficient electrochemical activation of the C-C bond of aryl ketones for the preparation of amides under catalyst- and external-oxidant-free conditions using aliphatic amines as the N source. Under environmentally benign electrolysis conditions, a series of amides were synthesized in good yield. Our control experiments revealed that electricity plays an important role in this transformation.

Metal-Free, Adjustable, and Recyclable Catalytic Systems for the Construction of C-C Bonds by Activating Propargylic Alcohols

Pyrano[3,2-c]coumarin derivatives and C3-substituted 4-hydroxycoumarins as important skeletal structures of active natural products and pharmaceutically relevant molecules have received increasing attention. However, developing an adjustable system for selectively synthesizing them is still a challenging task. Herein, sulfonic acid-functionalized ionic liquid was successfully used as the catalyst for the alkylation of 4-hydroxycoumarin derivatives with secondary aromatic propargylic alcohols using dimethyl carbonate as the green solvent, giving up to 98% yield. On the other hand, protonated imidazole-based ionic liquid-catalyzed cyclization was also selectively achieved with a nearly quantitative yield. Developed metal-free catalytic systems exhibited well adjustable and recyclable properties, avoiding the contamination of metal and halogen, reducing the neutralization after the reaction, and benefiting the separation between the catalyst and the product. New strategies were applied for performing the gram-scale reaction smoothly. The adjustable systems might occur through two different mechanisms involving propargylic or allenic carbocation and hydrogen bonding effects between the catalysts and the substrates.

Divergent Synthesis of 2-Cyanoaryl Carbamate and 2-Cyanoaryl Urea Derivatives via Hypervalent Iodine-Induced C-C Bond Cleavage

Divergent synthetic methods for transforming isatins to 2-cyanoaryl carbamate and 2-cyanoaryl urea derivatives were developed using ammonium carbamate as the nitrogen source and iodobenzene diacetate as the oxidant. This reaction features mild conditions, broad substrate scope, and moreover, the use of toxic cyano-containing compounds is avoided.

Iron-Promoted Oxidative Alkylation/Cyclization of Ynones with 4-Alkyl-1,4-dihydropyridines: Access to 2-Alkylated Indenones

An iron-promoted oxidative tandem alkylation/cyclization of ynones with 4-alkyl-substituted 1,4-dihydropyridines for the efficient synthesis of 2-alkylated indenones is described. The process occurs via oxidative homolysis of a C-C σ-bond in 1,4-dihydropyridines to generate an alkyl radical followed by the addition of C-C triple bonds in ynones and intramolecular cyclization. A wide range of alkyl radicals could be efficiently transferred to generate a series of synthetically useful 2-alkylated indenones with excellent selectivity under mild conditions.

Electrochemical ammonium-cation-assisted pyridylation of inert N-heterocycles via dual-proton-coupled electron transfer

A straightforward and practical strategy for pyridylation of inert N-heterocycles, enabled by ammonium cation and electrochemical, has been described. This protocol gives access to various N-fused heterocycles and bidentate nitrogen ligand compounds, through dual-proton-coupled electron transfer (PCET) and radical cross-coupling in the absence of exogenous metal and redox reagent. It features broad substrate scope, wide functional group tolerance, and easy gram-scale synthesis. Various experiments and density functional theory (DFT) calculation results show the mechanism of dual PCET followed by radical cross-coupling is the preferred pathway. Moreover, ammonium salt plays the dual role of protonation reagent and electrolyte in this conversion, and the resulting product 9-(pyridin-4-yl)acridine compound can be used for fluorescence recognition of Fe2+ and Pd2+ with high sensitivity.

Selective Coupling of 1,2-Bis-Boronic Esters at the more Substituted Site through Visible-Light Activation of Electron Donor-Acceptor Complexes

1,2-Bis-boronic esters are useful synthetic intermediates particularly as the two boronic esters can be selectively functionalized. Usually, the less hindered primary boronic ester reacts, but herein, we report a coupling reaction that enables the reversal of this selectivity. This is achieved through the formation of a boronate complex with an electron-rich aryllithium which, in the presence of an electron-deficient aryl nitrile, leads to the formation of an electron donor-acceptor complex. Following visible-light photoinduced electron transfer, a primary radical is generated which isomerizes to the more stable secondary radical before radical-radical coupling with the arene radical-anion, giving β-aryl primary boronic ester products. The reactions proceed under catalyst-free conditions. This method also allows stereodivergent coupling of cyclic cis-1,2-bis-boronic esters to provide trans-substituted products, complementing the selectivity observed in the Suzuki-Miyaura reaction.

Hydropyridylation of α,β-Unsaturated Esters through Electroreduction of 4-Cyanopyridine

A mild and highly efficient method for the hydropyridylation of α,β-unsaturated esters has been developed. This protocol provides the products smoothly with a wide substrate scope in an undivided cell under ambient conditions. Moreover, studies showed that the scope could be extended to other unsaturated compounds, including enones and aldehydes.

Switchable photocatalysis for the chemodivergent benzylation of 4-cyanopyridines

We report a photocatalytic strategy for the chemodivergent radical benzylation of 4-cyanopyridines. The chemistry uses a single photoredox catalyst to generate benzyl radicals upon N–F bond activation of 2-alkyl N-fluorobenzamides. The judicious choice of different photocatalyst quenchers allowed us to select at will between mechanistically divergent processes. The two reaction manifolds, an ipso-substitution path proceeding via radical coupling and a Minisci-type addition, enabled selective access to regioisomeric C4 or C2 benzylated pyridines, respectively. Mechanistic investigations shed light on the origin of the chemoselectivity switch.

We report a photocatalytic strategy for the chemodivergent radical benzylation of 4-cyanopyridines. The chemistry uses a single photoredox catalyst to generate benzyl radicals upon N–F bond activation of 2-alkyl N-fluorobenzamides.

Photoredox-catalyzed synthesis of sulfonated oxazolines from N-allylamides through the insertion of sulfur dioxide

Photoredox-catalyzed generation of sulfonated oxazolines starting from N-allylamides, DABCO·(SO2)2, and aryldiazonium salts has been developed and a range of sulfonated oxazolines were obtained in moderate to good yields.