- Mono- and Ditopic Bisfunctionalization of Graphene
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For the first time, the bisfunctionalization of graphene by employing two successive reduction and covalent bond forming steps is reported. Bulk functionalization in dispersion and functionalization of individual sheets deposited on surfaces have both been carried out. Whereas in the former case attacks from both sides of the basal plane are possible and can lead to strain-free architectures, in the latter case, retrofunctionalizations can become important when the corresponding anion of the addend is a sufficiently good leaving group.
- Knirsch, Kathrin C.,Sch?fer, Ricarda A.,Hauke, Frank,Hirsch, Andreas
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- Deprotection of arenediazonium tetrafluoroborate ethers with BBr 3
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(Chemical Equation Presented) Ether cleavage was carried out on arene bearing a diazonium salt. The deprotection takes place with boron tribromide under very mild conditions in good yields without affecting the diazonium group.
- Ngoc, Hoa Nguyen,Cougnon, Charles,Gohier, Frederic
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Read Online
- Aryl Radical Activation of C-O Bonds: Copper-Catalyzed Deoxygenative Difluoromethylation of Alcohols
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Given their ubiquity in natural products and pharmaceuticals, alcohols represent one of the most attractive starting materials for the construction of C-C bonds. We report herein the first catalytic strategy to harness the reactivity of aryl radicals for the activation of C-O bonds in alcohol-derived xanthate esters, allowing for the discovery of the first catalytic deoxygenative difluoromethylation reaction. Under copper-catalyzed conditions, a wide variety of alkyl xanthate esters, readily synthesized from alcohol feedstocks, were activated by catalytically generated aryl radicals and were converted to the alkyl-difluoromethane products via alkyl radical intermediates. This scalable protocol exhibits a broad substrate scope and functional group tolerance, enabling late-stage modification of complex pharmaceutical agents. A one-pot protocol has been developed that allows for the direct use of free alcohols without purification of the xanthate esters. Mechanistic studies are consistent with the hypothesis of aryl radicals being formed and initiating the cleavage of the C-O bonds of xanthate esters, to generate alkyl radicals as the key intermediates. This aryl radical activation approach represents a new strategy for the activation of alcohols as cross-coupling partners.
- Cai, Aijie,Liu, Wei,Yan, Wenhao
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supporting information
p. 9952 - 9960
(2021/07/21)
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- Metal-Free Visible-Light Synthesis of Arylsulfonyl Fluorides: Scope and Mechanism
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The first metal-free procedure for the synthesis of arylsulfonyl fluorides is reported. Under organo-photoredox conditions, aryl diazonium salts react with a readily available SO2 source (DABSO) to afford the desired product through simple nucleophilic fluorination. The reaction tolerates the presence of both electron-rich and -poor aryls and demonstrated a broad functional group tolerance. To shed the light on the reaction mechanism, several experimental techniques were combined, including fluorescence, NMR, and EPR spectroscopy as well as DFT calculations.
- Louvel, Dan,Chelagha, Aida,Rouillon, Jean,Payard, Pierre-Adrien,Khrouz, Lhoussain,Monnereau, Cyrille,Tlili, Anis
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supporting information
p. 8704 - 8708
(2021/05/17)
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- Aryl Diazonium Salts: Powerful Arylating Agents for Catellani-Typeortho-Arylation
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The Catellani reaction provides an efficient synthetic approach to polyfunctionalized arenes. However, the selectiveortho-arylating reagents employed in these reactions have been strictly limited to activated bromoarenes. As demonstrated in this work, aryl diazonium salts bearing both electron-donating and electron-withdrawing substituents, after in situ transformations with KI into the corresponding iodoarenes, were efficient arylating reagents for Catellani typeortho-arylation approaches.
- Fu, Ying,Guo, Liang-Liang,Zhang, Yu-Xia
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supporting information
p. 17437 - 17444
(2021/12/02)
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- Matsuda-Heck arylation of itaconates: A versatile approach to heterocycles from a renewable resource
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Itaconic acid esters and hemiesters undergo Pd-catalyzed coupling reactions with arene diazonium salts in high to excellent yields. The coupling products of ortho-nitro arene diazonium salts can be converted in one or two steps to benzazepine-2-ones.
- Krause, Andreas,Sperlich, Eric,Schmidt, Bernd
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supporting information
p. 4292 - 4302
(2021/05/31)
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- Chemical and Genetic Studies on the Formation of Pyrrolones During the Biosynthesis of Cytochalasans
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A key step during the biosynthesis of cytochalasans is a proposed Knoevenagel condensation to form the pyrrolone core, enabling the subsequent 4+2 cycloaddition reaction that results in the characteristic octahydroisoindolone motif of all cytochalasans. In this work, we investigate the role of the highly conserved α,β-hydrolase enzymes PyiE and ORFZ during the biosynthesis of pyrichalasin H and the ACE1 metabolite, respectively, using gene knockout and complementation techniques. Using synthetic aldehyde models we demonstrate that the Knoevenagel condensation proceeds spontaneously but results in the 1,3-dihydro-2H-pyrrol-2-one tautomer, rather than the required 1,5-dihydro-2H-pyrrol-2-one tautomer. Taken together our results suggest that the α,β-hydrolase enzymes are essential for first ring cyclisation, but the precise nature of the intermediates remains to be determined.
- Zhang, Haili,Hantke, Verena,Bruhnke, Pia,Skellam, Elizabeth J.,Cox, Russell J.
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supporting information
p. 3106 - 3113
(2021/01/20)
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- Aqueous and Visible-Light-Promoted C-H (Hetero)arylation of Uracil Derivatives with Diazoniums
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Direct C5 (hetero)arylation of uracil and uridine substrates with (hetero)aryl diazonium salts under photoredox catalysis with blue light was reported. The coupling proceeds efficiently with diazonium salts and heterocycles in good functional group tolerance at room temperature in aqueous solution without transition-metal components. A plausible radical mechanism has been proposed.
- Liu, An-Di,Wang, Zhao-Li,Liu, Li,Cheng, Liang
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p. 16434 - 16447
(2021/11/16)
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- Light- and Manganese-Initiated Borylation of Aryl Diazonium Salts: Mechanistic Insight on the Ultrafast Time-Scale Revealed by Time-Resolved Spectroscopic Analysis
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Manganese-mediated borylation of aryl/heteroaryl diazonium salts emerges as a general and versatile synthetic methodology for the synthesis of the corresponding boronate esters. The reaction proved an ideal testing ground for delineating the Mn species responsible for the photochemical reaction processes, that is, involving either Mn radical or Mn cationic species, which is dependent on the presence of a suitably strong oxidant. Our findings are important for a plethora of processes employing Mn-containing carbonyl species as initiators and/or catalysts, which have considerable potential in synthetic applications.
- Firth, James D.,Hammarback, L. Anders,Burden, Thomas J.,Eastwood, Jonathan B.,Donald, James R.,Horbaczewskyj, Chris S.,McRobie, Matthew T.,Tramaseur, Adam,Clark, Ian P.,Towrie, Michael,Robinson, Alan,Krieger, Jean-Philippe,Lynam, Jason M.,Fairlamb, Ian J. S.
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supporting information
p. 3979 - 3985
(2021/02/03)
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- Azoacetylenes for the Synthesis of Arylazotriazole Photoswitches
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We report a modular approach toward novel arylazotriazole photoswitches and their photophysical characterization. Addition of lithiated TIPS-acetylene to aryldiazonium tetrafluoroborate salts gives a wide range of azoacetylenes, constituting an underexplored class of stable intermediates.In situdesilylation transiently leads to terminal arylazoacetylenes that undergo copper-catalyzed cycloadditions (CuAAC) with a diverse collection of organoazides. These include complex molecules derived from natural products or drugs, such as colchicine, taxol, tamiflu, and arachidonic acid. The arylazotriazoles display near-quantitative photoisomerization and long thermalZ-half-lives. Using the method, we introduce for the first time the design and synthesis of a diacetylene platform. It permits implementation of consecutive and diversity-oriented approaches linking two different conjugants to independently addressable acetylenes within a common photoswitchable azotriazole. This is showcased in the synthesis of several photoswitchable conjugates, with potential applications as photoPROTACs and biotin conjugates.
- Anderl, Felix,Balkenhohl, Moritz,Carreira, Erick M.,Fink, Moritz,Pfaff, Patrick
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supporting information
p. 14495 - 14501
(2021/09/18)
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- Palladium-Catalyzed Formal (3 + 2) Cycloaddition Reactions of 2-Nitro-1,3-enynes with Vinylaziridines, -epoxides, and -cyclopropanes
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A two-step Pd-catalyzed (3 + 2) cycloaddition/HNO2 elimination reaction sequence has been developed to give novel cyclic 1,3-dien-5-yne systems from Pd-stabilized zwitterionic 1,3-dipoles and 2-nitro-1,3-enyne substrates. The process is highly atom-efficient and tolerates the reaction of 2-vinyloxirane, 1-tosyl-2-vinylaziridine, and diethyl 2-vinylcyclopropane-1,1-dicarboxylate derived 1,3-dipoles with a variety of 2-nitro-1,3-enyne substrates. The stereochemistry of the intermediate (3 + 2) cycloadducts was determined by single crystal X-ray analysis. Furthermore, a selective kinetic elimination of the cycloadduct with an antiperiplanar relationship between the NO2 group and the participating hydrogen was demonstrated, allowing for efficient isolation of a single diastereoisomer of the cycloadduct.
- Drew, Melanie A.,Tague, Andrew J.,Richardson, Christopher,Pyne, Stephen G.,Hyland, Christopher J. T.
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supporting information
p. 4635 - 4639
(2021/06/28)
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- Highly Efficient Synthesis of Hindered 3-Azoindoles via Metal-Free C-H Functionalization of Indoles
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Although 3-azoindoles have recently emerged as an appealing family of photoswitch molecules, the synthesis of such compounds has been poorly covered in the literature. Herein a high-yielding and operationally simple protocol is reported allowing the synthesis of 3-azoindoles, featuring important steric hindrance around the azo motif. Remarkably, this C-H coupling is characterized by excellent atom economy and occurs under metal-free conditions, at room temperature, and within few minutes, delivering the expected products in excellent yields (quantitatively in most of the cases). Accordingly, a library of new molecules, with potential applications as photochromic compounds, is prepared.
- Guillemard, Lucas,Jacob, Nicolas,Wencel-Delord, Joanna
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supporting information
p. 574 - 580
(2020/02/13)
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- Comparison of the Thermal Stabilities of Diazonium Salts and Their Corresponding Triazenes
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A range of diazonium salts and their corresponding triazenes have been prepared in order to directly compare their relative thermal stabilities (via initial decomposition temperature) from differential scanning calorimetry (DSC) data. A structure-stability relationship has been explored to investigate trends in stability, depending on the aromatic substituent and the structure of the secondary amine component of the diazonium salts and triazenes. All of the triazenes investigated show significantly greater stability (many are stable above 200 °C) compared with the corresponding diazonium salts, which show varying stabilities.
- Schotten, Christiane,Leprevost, Samy K.,Yong, Low Ming,Hughes, Colan E.,Harris, Kenneth D. M.,Browne, Duncan L.
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supporting information
p. 2336 - 2341
(2020/06/05)
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- Visible Light Induced Cyclization to Spirobi[indene] Skeletons from Functionalized Alkylidienecyclopropanes
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In this paper, we revealed a metal-free and visible light photoinduced method for the rapid construction of spirobi[indene] skeletons, providing a simple and efficient way for easy access to spirobi[indene] scaffolds under mild conditions along with a broad substrate scope and good functional group tolerance.
- Li, Quanzhe,Liu, Jiaxin,Shi, Min,Wei, Yin
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supporting information
(2020/03/26)
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- Heterogeneous visible-light-induced Meerwein hydration reaction of alkenes in water using mpg-C3N4 as a recyclable photocatalyst
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A green and efficient visible light induced Meerwein hydration reaction of alkenes in aqueous medium using mpg-C3N4 as a recyclabe photocatalyst has been disclosed. This protocol provides a direct approach for the preparation of racemic alcohols via a free radical mechanism. Water acted as both a solvent and a reagent without any additives or co-solvents. The metal-free heterogeneous semiconductor is found to be fully recyclable at least 5 times without any significant reduction in activity. The Meerwein hydration reaction has an excellent substrate scope and gave the desired products in moderate to high yields. Furthermore, this reaction could be carried out under solar light irradiation and is applicable for large-scale reactions with satisfactory results.
- Wang, Jingjing,Xue, Linshuang,Hong, Mei,Ni, Bangqing,Niu, Tengfei
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supporting information
p. 411 - 416
(2020/02/13)
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- Transition-Metal- A nd Light-Free Directed Amination of Remote Unactivated C(sp3)-H Bonds of Alcohols
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Due to the great value of amino alcohols, new methods for their synthesis are in high demand. Abundant aliphatic alcohols represent the ideal feedstock for the method development toward this important motif. To date, transition-metal-catalyzed approaches for the directed remote amination of alcohols have been well established. Yet, they have certain disadvantages such as the use of expensive catalysts and limited scope. Very recently, transition-metal-free visible-light-induced radical approaches have emerged as new powerful tools for directed remote amination of alcohols. Relying on 1,5-HAT reactivity, these methods are limited to β-or δ- A mination only. Herein, we report a novel transitionmetal- A nd visible-light-free room-temperature radical approach for remote β-, γ-, and δ-C(sp3)-N bond formation in aliphatic alcohols using mild basic conditions and readily available diazonium salt reagents.
- Kurandina, Daria,Yadagiri, Dongari,Rivas, Monica,Kavun, Aleksei,Chuentragool, Padon,Hayama, Keiichi,Gevorgyan, Vladimir
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supporting information
p. 8104 - 8109
(2019/06/13)
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- Irreversible tautomerization as a powerful tool to access unprecedented functional porous organic polymers with a tris(β-keto-hydrazo)cyclohexane subunit (TKH-POPs)
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Porous organic polymers (POPs) have received much attention, due to their multiple potential applications and flexibility in chemical structure design. Creation of a novel chemical structure has been the central task in the research of POPs, which are usually constructed by direct coupling polymerizations. The fascinating rearrangement/tautomerization could lead to some novel structures, which are hard to access by conventional direct coupling polymerizations. Herein, the tautomerization from tris(β-hydroxyl-azo)benzene to the tris(β-keto-hydrozo)cyclohexane structure has been proved unambiguously based on an advanced 2D NMR technique such as 15N-1H-HSQC and 1H-1H-NOESY. The crucial tautomerization was used to synthesize TKH-POPs for the first time. The as-synthesized TKH-POP-1 was found to have an adsorption capacity as high as 66.3 mmol g-1 (at 273 K and P/P0 = 0.98) towards acetonitrile vapor, which was the highest among all the reported materials. The general and flexible strategy to make functional POPs with tunable pores such as ultramicropores, micropores and mesopores will help develop interesting functional POPs in the near future.
- Liu, Xiangxiang,Luo, Xian-Sheng,Fu, Hao-Xi,Fan, Wenhao,Chen, Shi-Lu,Huang, Mu-Hua
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supporting information
p. 2103 - 2106
(2020/02/26)
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- Gold(I)-Catalyzed Cross-Coupling Reactions of Arenediazonium Salts with Alkynoic Acids
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Abstract: The reaction of simple alkynoate salts with isolated arenediazonium tetrafluoroborate salts that had been pre-conditioned with the gold(I) catalyst AuCl(Me2S) led to the formation of cross-coupled products via a decarboxylative Sonogashira reaction process in modest yield and under mild conditions. The major by-product is a defunctionalized aryl moiety stemming from the diazonium salt, which competitively forms via hydrodediazonation. Good functional group tolerance and reaction site selectivity were attained in this limited investigation.
- Abrams, J. N.,Chi, B. K.
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p. 1236 - 1244
(2020/09/17)
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- Rational Design of Azothiophenes—Substitution Effects on the Switching Properties
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A series of substituted azothiophenes was prepared and investigated toward their isomerization behavior. Compared to azobenzene (AB), the presented compounds showed red-shifted absorption and almost quantitative photoisomerization to their (Z) states. Furthermore, it was found that electron-withdrawing substitution on the phenyl moiety increases, while electron-donating substitution decreases the thermal half-lives of the (Z)-isomers due to higher or lower stabilization by a lone pair–π interaction. Additionally, computational analysis of the isomerization revealed that a pure singlet state transition state is unlikely in azothiophenes. A pathway via intersystem crossing to a triplet energy surface of lower energy than the singlet surface provided a better fit with experimental data of the (Z)→(E) isomerization. The insights gained in this study provide the necessary guidelines to design effective thiophenylazo-photoswitches for applications in photopharmacology, material sciences, or solar energy harvesting applications.
- Heindl, Andreas H.,Wegner, Hermann A.
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supporting information
p. 13730 - 13737
(2020/10/02)
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- Fluorosulfonylation of arenediazonium tetrafluoroborates with Na2S2O5 and N-fluorobenzenesulfonimide
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A transition-metal-free Sandmeyer-type fluorosulfonylation reaction has been achieved by the three-component reaction of arenediazonium tetrafluoroborates, Na2S2O5, and N-fluorobenzenesulfonimide (NFSI). The reaction proceeds through a radical tandem process, affording various arenesulfonyl fluorides in moderate to high yields. This protocol not only provides a complement to the previous fluorosulfonylation reactions, but also extends the applications of Sandmeyer reaction.
- Huang, Yangen,Liu, Shuai,Qing, Feng-Ling,Xu, Xiu-Hua
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- σ-Bond initiated generation of aryl radicals from aryl diazonium salts
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σ-Bond nucleophiles and molecular oxygen transform aryl diazonium salts into aryl radicals. Experimental and computational studies show that Hantzsch esters transfer hydride to aryl diazonium species, and that oxygen initiates radical fragmentation of the diazene intermediate to produce aryl radicals. The operational simplicity of this addition-fragmentation process for the generation of aryl radicals, by a polar-radical crossover mechanism, has been illustrated in a variety of bond-forming reactions.
- Chan, Bun,McErlean, Christopher S. P.,Nashar, Philippe E.,Tatunashvili, Elene
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supporting information
p. 1812 - 1819
(2020/03/17)
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- RhIII-Catalyzed Synthesis of Highly Substituted 2-Pyridones using Fluorinated Diazomalonate
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A RhIII-catalyzed strategy was developed for the rapid construction of highly substituted 2-pyridone scaffolds using α,β-unsaturated oximes and fluorinated diazomalonate. The reaction proceeds through direct, site-selective alkylation based on migratory insertion and subsequent cyclocondensation. A wide substrate scope with different functional groups was explored. The requirement of fluorinated diazomalonate was explored for this transformation. The developed methodology was further extended with the synthesis of the bioactive compound.
- Das, Debapratim,Sahoo, Gopal,Biswas, Aniruddha,Samanta, Rajarshi
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supporting information
p. 360 - 364
(2020/01/25)
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- Dual palladium-photoredox catalyzed chemoselective C-H arylation of phenylureas
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A highly chemoselective C-H arylation of phenylureas has been accomplished using dual palladium-photoredox catalysis at room temperature without any additives, base or external oxidants. Regioselective C-H arylation ofN,N'-diaryl substituted unsymmetrical phenylureas has also been accomplished by a careful choice of aryl groups.
- Babu, Sakamuri Sarath,Shahid,Gopinath, Purushothaman
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supporting information
p. 5985 - 5988
(2020/06/04)
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- Visible-Light-Mediated Ru-Catalyzed Synthesis of 3-(Arylsulfonyl)but-3-enals via Coupling of α-Allenols with Diazonium Salts and Sulfur Dioxide
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The first coupling of α-allenols, sulfur dioxide, and arenediazonium salts is presented. The three-component reaction which is promoted by visible light can be easily accomplished using DABSO as a sulfur dioxide surrogate in the presence of a photoredox catalyst. In this manner, a broad range of electron-rich and electron-deficient aryl substituents are well accommodated in the sulfonylation-rearrangement cascade to afford the 2,2-disubstituted 3-(arylsulfonyl)but-3-enals in reasonable yields. Based on control experiments, a radical mechanism which does imply 1,2-aryl migration has been proposed.
- Herrera, Fernando,Luna, Amparo,Almendros, Pedro
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supporting information
p. 9490 - 9494
(2020/12/21)
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- Phenalenyl Based Aluminum Compound for Catalytic C-H Arylation of Arene and Heteroarenes at Room Temperature
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Main group metal based catalysis has been considered to be a cost-effective alternative way to the transition metal based catalysis, due to the high abundance of main group metals in the Earth's crust. Among the main group metals, aluminum is the most abundant (7-8%) in the Earth's crust, making the development of aluminum based catalysts very attractive. So far, aluminum based compounds have been popularly used as Lewis acids in a variety of organic reactions, but chemical transformation demanding a redox based process has never utilized an Al(III) complex as a catalyst. Herein, we tuned the redox noninnocence behavior of a phenalenyl ligand by coupling with Al(III) ion, which subsequently can store the electron upon reduction with K to carry out direct C-H arylation of heteroarenes/mesitylene at ambient temperature. A mechanistic investigation revealed that a three-electron reduced phenalenyl based triradical aluminum(III) complex plays the key role in such catalysis. The electronic structure of the catalytically active triradical species has been probed using EPR spectroscopy, magnetic susceptibility measurements, and electronic structure calculations using a DFT method.
- Vardhanapu, Pavan K.,Ahmed, Jasimuddin,Jose, Anex,Shaw, Bikash Kumar,Sen, Tamal K.,Mathews, Amita A.,Mandal, Swadhin K.
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p. 289 - 299
(2019/01/10)
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- Photocatalyzed borylation using water-soluble quantum dots
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The synthesis of arylboronates by Sandmeyer-type reactions in the presence of water still remains a significant challenge. Herein, we report the use of water-soluble MPA-capped quantum dot (QD) photocatalysts for the borylation of diazonium salts in the presence of water. A biphasic system under mild acidic conditions remains critical to prevent decomposition and competitive disulphide bond formation. The present protocol offers a broader scope of substrates and borylating agents. Additionally, this catalytic system offers a significantly high turnover number (TON). The present methodology can effectively distinguish subtle reactivity differences between boronic acids and boronates. Mechanistic investigation suggests an excited-state electron transfer pathway.
- Chandrashekar, Hediyala B.,Maji, Arun,Halder, Ganga,Banerjee, Sucheta,Bhattacharyya, Sayan,Maiti, Debabrata
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supporting information
p. 6201 - 6204
(2019/06/07)
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- Electrochemical Cross-Coupling of C(sp2)?H with Aryldiazonium Salts via a Paired Electrolysis: an Alternative to Visible Light Photoredox-Based Approach
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Photoredox-based C?H bond functionalization constitutes one of the most powerful and atom-economical approaches to organic syntheses. During this type of reaction, single electron transfer takes place between the photocatalyst (PC) and redox- active substrates. Electrosynthesis also involves electron transfer between substrates and electrodes. In this paper, we focus upon electrochemical cross-coupling of C(sp2)?H with aryldiazonium salts and have developed an efficient electrochemical approach to the Minisci-type arylation reaction. The constant current paired electrosynthesis proceeds in a simple undivided cell without external supporting electrolyte, features a wide range of substrates and is easy to scale-up. These results demonstrate that photoredox-based cross-coupling of C(sp2)?H with aryldiazonium salts can also proceed successfully under paired electrolysis conditions, thereby contributing to understanding of the parallels between photosynthesis and electrosynthesis. (Figure presented.).
- Jiang, Yang-ye,Dou, Gui-yuan,Zhang, Luo-sha,Xu, Kun,Little, R. Daniel,Zeng, Cheng-chu
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supporting information
p. 5170 - 5175
(2019/11/13)
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- Light-Induced Mechanistic Divergence in Gold(I) Catalysis: Revisiting the Reactivity of Diazonium Salts
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In a systematic study of the Au-catalyzed reaction of o-alkynylphenols with aryldiazonium salts, we find that essentially the same reaction conditions lead to a change in mechanism when a light source is applied. If the reaction is carried out at room temperature using a AuI catalyst, the diazonium salt undergoes electrophilic deauration of a vinyl AuI intermediate and provides access to substituted azobenzofurans. If the reaction mixture is irradiated with blue LED light, C?C bond formation due to N2-extrusion from the diazonium salt is realized selectively, using the same starting materials without the need for an additional photo(redox) catalyst under aerobic conditions. We report a series of experiments demonstrating that the same vinyl AuI intermediate is capable of producing the observed products under photolytic and thermal conditions. The finding that a vinyl AuI complex can directly, without the need for an additional photo(redox) catalyst, result in C?C bond formation under photolytic conditions is contrary to the proposed mechanistic pathways suggested in the literature till date and highlights that the role of oxidation state changes in photoredox catalysis involving Au is thus far only poorly understood and may hold surprises for the future. Computational results indicate that photochemical activation can occur directly from a donor–acceptor complex formed between the vinyl AuI intermediate and the diazonium salt.
- Taschinski, Svenja,D?pp, René,Ackermann, Martin,Rominger, Frank,de Vries, Folkert,Menger, Maximilian F. S. J.,Rudolph, Matthias,Hashmi, A. Stephen K.,Klein, Johannes E. M. N.
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supporting information
p. 16988 - 16993
(2019/11/13)
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- Generation of 1,3-Dimethylene-Substituted Isobenzofurans via Pd(II)-Catalyzed Selective Oxo-cyclization/SO2 Insertion Cascade of β-Alkynyl Ketones
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A new palladium(II)-catalyzed cyclization-radical addition cascade enables the direct construction of 1,3-dimethylene-substituted isobenzofuran derivatives containing a vinyl aryl sulfone unit in good yields by treating with β-alkynyl ketones, aryl diazonium salts, and DABCO·(SO2)2. The oxidant-free multicomponent reaction features good substrate scope and functional group tolerance, which proceeds through a sequence of Heck coupling, oxo-cyclization, and SO2 insertion.
- Liu, Shuai,Chen, Ke,Hao, Wen-Juan,Tu, Xing-Chao,Tu, Shu-Jiang,Jiang, Bo
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p. 1964 - 1971
(2019/05/16)
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- Copper(I)-promoted trifluoromethylthiolation of arenediazonium salts with AgSCF3
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An efficient method for trifluoromethylthiolation of arenediazonium salts has been developed in mild conditions with a stable and convenient AgSCF3. It provides a straightforward and convenient way for the synthesis of trifluoromethylthiolated compound from diazonium salts in moderate to good yields.
- Zheng, Changge,Liu, Yang,Hong, Jianquan,Huang, Shuai,Zhang, Wei,Yang, Yupeng,Fang, Ge
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supporting information
p. 1404 - 1407
(2019/05/01)
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- Visible-light-mediated direct C3-arylation of 2: H -indazoles enabled by an electron-donor-acceptor complex
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A mild visible-light-mediated, photocatalyst-free arylation of 2H-indazoles was developed. The formation of an electron donor-acceptor complex by 2H-indazoles and aryl diazonium salts in the presence of pyridine allows the direct arylation of 2H-indazoles under visible-light irradiation. This process provides an efficient route for the synthesis of C3-arylated-2H-indazoles, which are important scaffolds of various bioactive compounds.
- Aganda, Kim Christopher C.,Kim, Junyoung,Lee, Anna
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supporting information
p. 9698 - 9702
(2019/12/02)
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- Visible-Light-Mediated Hydroxycarbonylation of Diazonium Salts
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A visible light-promoted catalytic photoredox hydroxycarbonylation was achieved on aryl diazonium salts whether preformed or generated in situ from the corresponding anilines. This strategy allows a straightforward access to a variety of carboxylic acids under mild conditions. (Figure presented.).
- Gosset, Cyrille,Pellegrini, Sylvain,Jooris, Romain,Bousquet, Till,Pelinski, Lydie
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supporting information
p. 3401 - 3405
(2018/08/06)
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- Practical Reagents and Methods for Nucleophilic and Electrophilic Phosphorothiolations
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New late-stage phosphorothiolation methods are disclosed that allow the efficient transfer of SP(O)(OR)2 groups to diversely functionalized substrates using nucleophilic and electrophilic reagents. The nucleophilic reagent, tetramethylammonium O,O-dimethyl phosphorothioate, was synthesized in near-quantitative yield from Me3SiP(O)(OMe)2, elemental sulfur and Me4NF. Its umpolung with N-bromophthalimide provided the electrophilic reagent, O,O-dimethyl-S-(N-phthalimido)phosphorothioate. Complementary methods based on these reagents enable the phosphorothiolation of diversely functionalized alkyl halides, arenediazonium salts, arylboronic acids and electron-rich arenes in good yields under mild conditions. (Figure presented.).
- Kovács, Szabolcs,Bayarmagnai, Bilguun,Aillerie, Alexandre,Goo?en, Lukas J.
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supporting information
p. 1913 - 1918
(2018/03/30)
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- Mild-Base-Promoted Arylation of (Hetero)Arenes with Anilines
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Transition metal-free radical arylation of heteroarenes is achieved at room temperature by simply adding aqueous sodium carbonate to a solution of the corresponding heteroarene and arenediazonium salt, which can even be formed in situ. Such an easy, inexpensive and mild methodology has been optimized and applied to the expeditious modification of interesting molecular cores like naphthylimide or bisthienylcyclopentenes.
- Monzón, Diego M.,Santos, Tanausú,Pinacho-Crisóstomo,Martín, Víctor S.,Carrillo, Romen
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p. 325 - 333
(2018/01/15)
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- An Iron-Based Long-Lived Catalyst for Direct C?H Arylation of Arenes and Heteroarenes
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Direct C?H arylation of arenes and heteroarenes to biaryls at ambient temperature has been accomplished using a phenalenyl-supported iron(III) catalyst. The present catalyst requires a chemical reductant such as potassium and functions without any light stimulation. C?H arylation of various heteroarenes including pyridine as well as unactivated arene such as benzene delivered good to excellent yield (28 examples, up to 92 %) at room temperature. A combined effort based on experiments and theoretical calculations established that a phenalenyl-based radical species (generated by chemical reduction of the iron(III) coordinated phenalenyl complex) plays key role during the catalysis. Furthermore, this catalyst displayed remarkable stability during the catalysis, as evident from the fact that it was still usable over ten consecutive catalytic runs without losing its catalytic efficiency.
- Chakraborty, Soumi,Ahmed, Jasimuddin,Shaw, Bikash Kumar,Jose, Anex,Mandal, Swadhin K.
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supporting information
p. 17651 - 17655
(2018/11/10)
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- Cobalt bis(acetylacetonate)–tert-butyl hydroperoxide–triethyl-silane: A general reagent combination for the Markovnikov-selective hydrofunctionalization of alkenes by hydrogen atom transfer
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We show that cobalt bis(acetylacetonate) [Co(acac)2], tert-butyl hydroperoxide (TBHP), and triethylsilane (Et3SiH) constitute an inexpensive, general, and practical reagent combination to initiate a broad range of Markovnikov-selective alkene hydrofunctionalization reactions. These transformations are believed to proceed by cobalt-mediated hydrogen atom transfer (HAT) to the alkene substrate, followed by interception of the resulting alkyl radical intermediate with a SOMOphile. In addition, we report the first reductive couplings of unactivated alkenes and aryldiazonium salts by an HAT pathway. The simplicity and generality of the Co(acac)2–TBHP–Et3SiH reagent combination suggests it as a useful starting point to develop HAT reactions in complex settings.
- Ma, Xiaoshen,Herzon, Seth B.
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supporting information
p. 2259 - 2265
(2018/09/14)
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- Palladium catalyzed stereocontrolled synthesis of C-aryl glycosides using glycals and arenediazonium salts at room temperature
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A stereocontrolled synthesis of aryl-C-glycosides was achieved using glycals and aryldiazonium salts in the presence of palladium acetate. A wide range of glycals including d-glucal, d-galactal, l-rhamnal, d-xylal and d-ribal underwent C-arylation at the anomeric carbon in the presence of different aryldiazonium tetrafluoroborates and gave synthetically useful 2,3-deoxy-3-keto-α-aryl-C-glycosides in good to excellent yields. Broad substrate scope, simple operation and room temperature reactions make this protocol very attractive in organic synthesis.
- Singh, Adesh Kumar,Kandasamy, Jeyakumar
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supporting information
p. 5107 - 5112
(2018/07/29)
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- Synthesis of Chiral Sulfonyl Lactones via Copper-Catalyzed Asymmetric Radical Reaction of DABCO?(SO2)
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In the present work, an asymmetric copper-catalyzed radical multi-component cascade reaction of an unsaturated carboxylic acid, aryldiazonium tetrafluoroborate, and DABCO?(SO2)2 (DABSO) has been developed for the enantioselective synthesis of sulfonyl lactones. In this reaction, this SO2 surrogate, DABSO was applied for the first time in the construction of chiral compounds. This multiple-step asymmetric radical reaction was carried out under mild conditions and tolerated a wide range of substrates, resulting in the corresponding sulfonyl lactones with up to 95% chemical yields and 88% ee. The current reaction enriches the research contents of DABSO, and provides a new and efficient strategy to chiral functionalized lactones bearing quarternary stereogenic center. (Figure presented.).
- Wang, Yang,Deng, Lingling,Zhou, Jie,Wang, Xiaochen,Mei, Haibo,Han, Jianlin,Pan, Yi
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supporting information
p. 1060 - 1065
(2018/01/22)
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- New transmetalation reagents for the gold-catalyzed visible light-enabled C(sp or sp2)-C(sp2) cross-coupling with aryldiazonium salts in the absence of a photosensitizer
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The scope of photosensitizer-free visible light-driven gold-catalyzed cross-coupling was evaluated by a wide variety of organoboron and organosilicon species using four equivalents of aryldiazonium salts and (4-CF3-C6H4)3PAuCl in MeOH. In addition, a C(sp or sp2)-C(sp2) cross-coupling of organotrimethylsilanes and aryldiazonium salts was investigated. The reactions can be conducted under very mild reaction conditions, with a reduced amount of aryldiazonium salt (1.2 equiv.) by using a catalytic amount of Ph3PAuNTf2 in MeCN under irradiation with blue LEDs at room temperature.
- Witzel, Sina,Sekine, Kohei,Rudolph, Matthias,Hashmi, A. Stephen K.
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supporting information
p. 13802 - 13804
(2018/12/14)
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- A six-amino acid salt synthesis method (by machine translation)
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The embodiment of the invention provides a six-amino acid salt synthesis method. The method comprises: shown in formula I 1, 3, 5 - three amino as reaction raw material, under the alkaline condition is shown with the structural formula III coupling reaction of the diazonium salt, filtering and drying process as shown in the structural formula IV obtained after six-substituted P-amino; Reducing the micromotion substituted P-composition, adding hydrochloric acid reagent, prepared as shown in the structural formula V six amino hydrochloride. The present invention provides synthetic method has simple process, raw material sources are extensive, low cost of raw materials, the reaction speed is fast, high yield, the product is easy to separation and purification and the like. (by machine translation)
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Paragraph 0150; 0151-0155
(2019/01/14)
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- Visible-Light-Mediated Monoselective Ortho C-H Arylation of 6-Arylpurine Nucleosides with Diazonium Salts
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A combined palladium- and photoredox-catalyzed monoselective arylation of 6-arylpurine nucleosides has been developed by employing purine as a directing group via the photoredox reaction, and many functional groups are well tolerated in this direct C-H arylation condition. Various of functionalized purines (nucleosides) which are potentially of great importance in medicinal chemistry could be obtained under visible light irradiation at room temperature within 4 h.
- Liang, Lei,Xie, Ming-Sheng,Wang, Hai-Xia,Niu, Hong-Ying,Qu, Gui-Rong,Guo, Hai-Ming
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p. 5966 - 5973
(2017/06/07)
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- Copper-Catalyzed Arylsulfonylation and Cyclizative Carbonation of N-(Arylsulfonyl)acrylamides Involving Desulfonative Arrangement toward Sulfonated Oxindoles
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Sulfonated oxindoles are accessed by a Cu(OAc)2-catalyzed three-component reaction of N-(arylsulfonyl)acrylamides, DABSO, and aryldiazonium tetrafluoroborates. This transformation is triggered by the formation of arylsulfonyl radicals in situ from the reaction of aryldiazonium tetrafluoroborates and DABSO. Afterward, the sequential radical addition, radical cyclization, and desulfonylative 1,4-aryl migration take place to provide the final product by the formation of four new bonds in one pot. This procedure shows good functional group tolerance.
- Wang, Hepan,Sun, Song,Cheng, Jiang
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supporting information
p. 5844 - 5847
(2017/11/10)
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- Combining Sanford Arylations on Benzodiazepines with the Nuisance Effect
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5-Phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-ones react under palladium- and visible light photoredox catalysis, in refluxing methanol, with aryldiazonium salts to afford the respective 5-(2-arylphenyl) analogues. With 2- or 4-fluorobenzenediazonium derivatives, both fluoroaryl- and methoxyaryl- products were obtained, the latter resulting from a SNAr on the fluorobenzenediazonium salt (“nuisance effect”). A computational DFT analysis of the palladium-catalysed and the palladium/ruthenium-photocalysed mechanism for the functionalization of benzodiazepines indicated that, in the presence of the photocatalyst, the reaction proceeds via a low-energy SET pathway avoiding the high-energy oxidative addition step in the palladium-only catalysed reaction pathway. (Figure presented.).
- Khan, Raysa,Boonseng, Sarote,Kemmitt, Paul D.,Felix, Robert,Coles, Simon J.,Tizzard, Graham J.,Williams, Gareth,Simmonds, Olivia,Harvey, Jessica-Lily,Atack, John,Cox, Hazel,Spencer, John
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p. 3261 - 3269
(2017/09/06)
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- Erythrosine B Catalyzed Visible-Light Photoredox Arylation–Cyclization of N-Alkyl-N-aryl-2-(trifluoromethyl)acrylamides to 3-(Trifluoromethyl)indolin-2-one Derivatives
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3-Trifluoromethylindoline-2-one derivatives were prepared in a visible-light photocatalytic transformation of acrylamides. The arylation–cyclization sequence was initiated by light-induced aryl radical generation from aryldiazonium salts with the utilization of erythrosine B as an organic photocatalyst.
- Gonda, Zsombor,Béke, Ferenc,Tischler, Orsolya,Petró, Milán,Novák, Zoltán,Tóth, Balázs L.
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supporting information
p. 2112 - 2117
(2017/04/24)
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- Cascade annulations of aryldiazonium salts, nitriles and halo-alkynes leading to 3-haloquinolines
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A regiospecific access to 3-haloquinolines has been developed via a three-component annulation of aryldiazonium salts, nitriles and haloalkynes. This reaction proceeds through an initial formation of reactive nitrilium ion and further cascade annulation with haloalkynes. This method provides a straightforward access to a diverse array of functionalized quinolones (28 examples) under mild conditions and exhibits broad functional group tolerance. Applications of this method in a gram scale reaction and a formal synthesis of Pitavastatin are illustrated.
- Ramanathan, Mani,Liu, Shiuh-Tzung
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p. 4317 - 4322
(2017/06/30)
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- Visible-Light-Promoted C-H Arylation by Merging Palladium Catalysis with Organic Photoredox Catalysis
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The use of a dual palladium/organic photoredox catalytic system enables the directed arylation of arenes with aryldiazonium salts with a broad substrate scope at room temperature under mild reaction conditions. This study thus serves as not only an alternative route for the biaryl motifs but also a new example for the application of an organic photoredox catalyst.
- Jiang, Jian,Zhang, Wen-Man,Dai, Jian-Jun,Xu, Jun,Xu, Hua-Jian
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p. 3622 - 3630
(2017/04/11)
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- Tandem and chemoselective synthesis of benzil derivatives from styrene and arene diazonium salts
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A facile and practically applied protocol for synthesis of benzil derivatives using styrene and arene diazonium salts is reported. Pd(OAc)2/SeO2 catalytic system was found to be efficient for chemoselective synthesis of benzil. Selenium dioxide works well as an oxidant under milder reaction conditions. Moderate to very good yields of the desired products were obtained.
- Jadhav, Vilas G.,Sarode, Sachin A.,Nagarkar, Jayashree M.
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supporting information
p. 1834 - 1838
(2017/04/21)
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- Efficient copper-catalyzed N-arylation of NH-containing heterocycles and sulfonamides with arenediazonium tetrafluoroborates
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A practical copper-catalyzed N-arylation of NH-containing heterocycles with arenediazonium tetrafluoroborates has been developed using CuCl as catalyst and K2CO3 as additive under ligand-free conditions. This reaction system has wide substrate scope including imides, 1H-pyrazole, 1H-tetrazoles, 1,2-benzisothiazol-3(2H)-one, and related sulfonamides and gives moderate to excellent yields (up to 95%) of the desired products. This strategy is very general, simple, environmentally friendly, and tolerant of oxygen.
- Ouyang, Yu-Qing,Yang, Zhen-Hua,Chen, Zhong-Hui,Zhao, Sheng-Yin
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supporting information
p. 771 - 778
(2017/04/06)
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- Gold-catalysed cross-coupling between aryldiazonium salts and arylboronic acids: Probing the usefulness of photoredox conditions
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The synthesis of biaryl compounds from aryldiazonium salts and arylboronic acids was achieved using PPh3AuCl as catalyst, CsF as base and acetonitrile as solvent. Combined to photosensitizers, irradiation by blue LEDs allowed accelerating the reaction and expanding its scope. Various functional groups were compatible including bromoaryls, iodoaryls, aldehydes and alcohols. A 2-iodobenzyl alcohol moiety was smoothly introduced by this method, enabling its consecutive isotopic labelling by a Pd-catalysed alkoxycarbonylation.
- Cornilleau, Thomas,Hermange, Philippe,Fouquet, Eric
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supporting information
p. 10040 - 10043
(2016/08/15)
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- The promoting effect of pyridine ligands in the Pd-catalysed Heck-Matsuda reaction
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An efficient Pd-catalyzed arylation reaction of challenging acyclic olefins, in the presence of an organic ligand, has been disclosed. Commercially available cheap pyridine-based ligands are able to promote good to excellent yields for poorly efficient Heck-Matsuda arylation reactions of several allylic alcohols. A wide range of electronically different arenediazonium salts bearing either electron-releasing or withdrawing groups have been used allowing the synthesis of a range of β-aryl-methoxy-lactols. The catalytic system has been optimised, along with the reaction conditions, in order to achieve remarkable yields in less than 1 h.
- Khodja, Walid,Leclair, Alexandre,Rull-Barrull, Jordi,Zammattio, Fran?oise,Kutonova, Ksenia V.,Trusova, Marina E.,Felpin, Fran?ois-Xavier,Rodriguez-Zubiri, Mireia
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p. 8855 - 8862
(2016/10/11)
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- Preparation method of 5-phenyl-1-(4-methoxy phenyl)-1H-tetrazole
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The invention relates to a preparation method of 5-phenyl-1-(4-methoxy phenyl)-1H-tetrazole. The preparation method includes the steps of firstly, mixing 4-anisidine, water and fluoroboric acid aqueous solution, dropwisely adding sodium nitrite aqueous solution while stirring at 0-5 DEG C, then rising the temperature to room temperature, continuing the stirring reaction for 1-2 hours, and performing suction filtration to obtain 4-methoxy phenyl diazonium tetrafluoroborate; secondly, stirring and mixing 5-phenyl-1H-tetrazole, alkali and copper salt catalyst with solvent at the temperature from minus 5 DEG C to 5 DEG C, adding the 4-methoxy phenyl diazonium tetrafluoroborate in batch, allowing for reaction for 6-8 hours while stirring at the temperature from minus 5 DEG C to room temperature, extracting after the reaction, drying, evaporating to remove the solvent, and recrystallizing to obtain the 5-phenyl-1-(4-methoxy phenyl)-1H-tetrazole. The preparation method has the advantages that the method uses copper salt as the catalyst, the reaction time is shortened, and the yield is increased at the same time; the method is easy in initial raw material obtaining, low in cost, simple in reaction operation, short in reaction path, easy in industrial production and promising in application prospect.
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Paragraph 0040; 0041; 0042; 0043
(2017/04/26)
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