cas 459-44-9, 4-methylbenzenediazonium tetrafluoroborate

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On-off QD switch that memorizes past recovery from quenching by diazonium salts
The understanding of the interaction of CdSe/ZnS semiconductor quantum dots (QD) with their chemical environment is fundamental, yet far from being fully understood. p-Methylphenyldiazonium tetrafluoroborate has been used to get some insight into the effect of diazonium salts on the spectroscopy of QD. Our study reveals that the surface of CdSe/ZnS quantum dots can be modified by diazonium salts (although not functionalized), showing and on-off fluorescence behaviour that memorizes past quenching recoveries. Facile modification of the surface confers protection against quenching by new molecules of diazonium salt and other known quenchers such as 4-amino-TEMPO. The reaction mechanism has been explored in detail by using different spectroscopic techniques. At the first time after addition of diazonium salt over QD the fluorescent is turned off with Stern-Volmer behaviour; the fluorescence recovers following irradiation. Subsequent additions of diazonium salts do not cause the same degree of quenching. We have noted that the third addition (following two cycles of addition and irradiation) is unable to quench the fluorescence. Monitoring the process using NMR techniques reveals the formation of p-difluoroborane toluene as a result of the irradiation of diazonium-treated QD; the treatment leads to the fluorination of the QD surface.
Liras, Marta,Gonzalez-Bejar, Maria,Scaiano
p. 9757 - 9762
(2010)
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Azoacetylenes for the Synthesis of Arylazotriazole Photoswitches
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
supporting information
p. 14495 - 14501
(2021/09/18)

Aqueous and Visible-Light-Promoted C-H (Hetero)arylation of Uracil Derivatives with Diazoniums
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
p. 16434 - 16447
(2021/11/16)

Metal-Free Visible-Light Synthesis of Arylsulfonyl Fluorides: Scope and Mechanism
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
supporting information
p. 8704 - 8708
(2021/05/17)

Fluorosulfonylation of arenediazonium tetrafluoroborates with Na2S2O5 and N-fluorobenzenesulfonimide
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
(2020/10/18)

Modular and Selective Arylation of Aryl Germanes (C?GeEt3) over C?Bpin, C?SiR3 and Halogens Enabled by Light-Activated Gold Catalysis
Selective C (Formula presented.) –C (Formula presented.) couplings are powerful strategies for the rapid and programmable construction of bi- or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd-catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd0/PdII catalysis) in the presence of the valuable functionalities C?BPin, C?SiMe3, C?I, C?Br, C?Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C?Ge with aryl diazonium salts. Contrary to previous light-/gold-catalyzed couplings of Ar–N2+, which were specialized in Ar–N2+ scope, we present conditions to efficiently couple electron-rich, electron-poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron-poor Ar–N2+ salts are readily activated by gold under blue-light irradiation, there is a competing dissociative deactivation pathway for excited electron-rich Ar–N2+, which requires an alternative photo-redox approach to enable productive couplings.
Dahiya, Amit,Fricke, Christoph,Funes-Ardoiz, Ignacio,Gevondian, Avetik G.,Schoenebeck, Franziska,Sherborne, Grant J.
supporting information
p. 15543 - 15548
(2020/06/22)

Thiophenylazobenzene: An Alternative Photoisomerization Controlled by Lone-Pair???π Interaction
Azoheteroarene photoswitches have attracted attention due to their unique properties. We present the stationary photochromism and ultrafast photoisomerization mechanism of thiophenylazobenzene (TphAB). It demonstrates impressive fatigue resistance and photoisomerization efficiency, and shows favorably separated (E)- and (Z)-isomer absorption bands, allowing for highly selective photoconversion. The (Z)-isomer of TphAB adopts an unusual orthogonal geometry where the thiophenyl group is perfectly perpendicular to the phenyl group. This geometry is stabilized by a rare lone-pair???π interaction between the S atom and the phenyl group. The photoisomerization of TphAB occurs on the sub-ps to ps timescale and is governed by this interaction. Therefore, the adoption and disruption of the orthogonal geometry requires significant movement along the inversion reaction coordinates (CNN and NNC angles). Our results establish TphAB as an excellent photoswitch with versatile properties that expand the application possibilities of AB derivatives.
Slavov, Chavdar,Yang, Chong,Heindl, Andreas H.,Wegner, Hermann A.,Dreuw, Andreas,Wachtveitl, Josef
supporting information
p. 380 - 387
(2019/11/25)

Dual palladium-photoredox catalyzed chemoselective C-H arylation of phenylureas
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
supporting information
p. 5985 - 5988
(2020/06/04)

Irreversible tautomerization as a powerful tool to access unprecedented functional porous organic polymers with a tris(β-keto-hydrazo)cyclohexane subunit (TKH-POPs)
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
supporting information
p. 2103 - 2106
(2020/02/26)

Copper-mediated tandem ring-opening/cyclization reactions of cyclopropanols with aryldiazonium salts: Synthesis of: N -arylpyrazoles
A general method for the synthesis of structurally diverse N-arylpyrazoles from readily available cyclopropanols and aryldiazonium salts is disclosed. The reaction was conducted at room temperature within minutes with a broad substrate scope and excellent regioselectivity.
Liu, Jidan,Xu, Erjie,Jiang, Jinyuan,Huang, Zeng,Zheng, Liyao,Liu, Zhao-Qing
supporting information
p. 2202 - 2205
(2020/02/26)

Visible Light Induced Cyclization to Spirobi[indene] Skeletons from Functionalized Alkylidienecyclopropanes
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
supporting information

(2020/03/26)

Transition-Metal- A nd Light-Free Directed Amination of Remote Unactivated C(sp3)-H Bonds of Alcohols
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
supporting information
p. 8104 - 8109
(2019/06/13)

Additions to N-Sulfinylamines as an Approach for the Metal-free Synthesis of Sulfonimidamides: O-Benzotriazolyl Sulfonimidates as Activated Intermediates
Sulfonimidamides are obtained in moderate to very good yields from the key intermediates O-benzotriazolyl sulfonimidates, which are formed by reacting aryldiazonium tetrafluoroborates, N-tritylsulfinylamine, and N-hydroxybenzotriazole hydrate in a process mediated by a tertiary amine. The formation of the sulfonimidate proceeds in inexpensive and environmentally benign dimethyl carbonate as the solvent, it does not require anhydrous conditions, and the product yields generally exceed 70 %. The substrate scope is broad, and a wide range of sensitive organic functionalities is well tolerated. The reactions probably proceed via aryl radicals formed from diazonium cations with assistance from both the tertiary amine and the sulfinylamine.
Bremerich, Maximilian,Conrads, Christian M.,Langletz, Tim,Bolm, Carsten
supporting information
p. 19014 - 19020
(2019/11/22)

Facile Synthesis of Tuneable Azophosphonium Salts
Azophosphonium salts have a facile synthesis and can be readily tuned at the para position of the aryl group and at the phosphorus position with the use of bulky phosphines, leading to a range of coloured compounds. A relation between the Hammett σ+para constant and the colour and 31P NMR chemical shift was explored. The compounds were characterised by NMR spectroscopy, UV/Vis spectroscopy and single-crystal X-ray structure crystallography.
Habraken, Evi R. M.,van der Zee, Lars J. C.,van de Vrande, Koen N. A.,Jupp, Andrew R.,Nieger, Martin,Ehlers, Andreas W.,Slootweg, J. Chris
p. 1594 - 1603
(2019/02/09)

Light-Induced Mechanistic Divergence in Gold(I) Catalysis: Revisiting the Reactivity of Diazonium Salts
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.
supporting information
p. 16988 - 16993
(2019/11/13)

Generation of 1,3-Dimethylene-Substituted Isobenzofurans via Pd(II)-Catalyzed Selective Oxo-cyclization/SO2 Insertion Cascade of β-Alkynyl Ketones
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
p. 1964 - 1971
(2019/05/16)

Copper(I)-promoted trifluoromethylthiolation of arenediazonium salts with AgSCF3
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
supporting information
p. 1404 - 1407
(2019/05/01)

Phenalenyl Based Aluminum Compound for Catalytic C-H Arylation of Arene and Heteroarenes at Room Temperature
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.
p. 289 - 299
(2019/01/10)

Preparation of N-Arylquinazolinium Salts via a Cascade Approach
An easy manipulation method for the preparation of N-arylquinazolinium salts is described from readily available aryldiazonium salts, nitriles, and 2-aminoarylketones in a one-pot operation. This method relies on the in situ generation of the N-arylnitrilium intermediate from the reaction of aryldiazonium salt with nitrile, which undergoes amination/cascade cyclization/aromatization, leading to N-arylquinazolinium salts in excellent yields. Nucleophilic addition of alkoxide to these N-arylquinazolinium salts provides functionalized dihydro-N-arylquinazoline.
Ramanathan, Mani,Wan, Jing,Liu, Shiuh-Tzung
p. 7459 - 7467
(2019/06/14)

Photocatalyzed borylation using water-soluble quantum dots
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
supporting information
p. 6201 - 6204
(2019/06/07)

Electrochemical Cross-Coupling of C(sp2)?H with Aryldiazonium Salts via a Paired Electrolysis: an Alternative to Visible Light Photoredox-Based Approach
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
supporting information
p. 5170 - 5175
(2019/11/13)

An Iron-Based Long-Lived Catalyst for Direct C?H Arylation of Arenes and Heteroarenes
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.
supporting information
p. 17651 - 17655
(2018/11/10)

Synthesis of Chiral Sulfonyl Lactones via Copper-Catalyzed Asymmetric Radical Reaction of DABCO?(SO2)
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
supporting information
p. 1060 - 1065
(2018/01/22)

A six-amino acid salt synthesis method (by machine translation)
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 0133; 0134-0138

(2019/01/14)

Palladium catalyzed stereocontrolled synthesis of C-aryl glycosides using glycals and arenediazonium salts at room temperature
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
supporting information
p. 5107 - 5112
(2018/07/29)

Visible-Light-Mediated Hydroxycarbonylation of Diazonium Salts
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
supporting information
p. 3401 - 3405
(2018/08/06)

Hypervalent Iodine(III)-Catalyzed Balz–Schiemann Fluorination under Mild Conditions
An unprecedented hypervalent iodine(III) catalyzed Balz–Schiemann reaction is described. In the presence of a hypervalent iodine compound, the fluorination reaction proceeds under mild conditions (25–60 °C), and features a wide substrate scope and good functional-group compatibility.
Xing, Bo,Ni, Chuanfa,Hu, Jinbo
supporting information
p. 9896 - 9900
(2018/07/31)

TOLL-LIKE RECEPTOR ANTAGONIST COMPOUNDS AND METHODS OF USE
The invention relates to compounds of formula (I): or a salt or solvate thereof, wherein the variables are as described herein. Compounds of formula (I) and pharmaceutical compositions thereof are antagonists of toll-like receptors such as TLR7, TLR8 and/or TLR9 that are useful for inhibiting immune response and treating diseases associated with undesirable immune response.
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Paragraph 0308

(2018/05/27)

Erythrosine B Catalyzed Visible-Light Photoredox Arylation–Cyclization of N-Alkyl-N-aryl-2-(trifluoromethyl)acrylamides to 3-(Trifluoromethyl)indolin-2-one Derivatives
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.
supporting information
p. 2112 - 2117
(2017/04/24)

Visible-Light-Mediated Monoselective Ortho C-H Arylation of 6-Arylpurine Nucleosides with Diazonium Salts
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
p. 5966 - 5973
(2017/06/07)

Copper-Catalyzed Arylsulfonylation and Cyclizative Carbonation of N-(Arylsulfonyl)acrylamides Involving Desulfonative Arrangement toward Sulfonated Oxindoles
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
supporting information
p. 5844 - 5847
(2017/11/10)

Visible-Light-Promoted C-H Arylation by Merging Palladium Catalysis with Organic Photoredox Catalysis
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
p. 3622 - 3630
(2017/04/11)

Tandem and chemoselective synthesis of benzil derivatives from styrene and arene diazonium salts
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.
supporting information
p. 1834 - 1838
(2017/04/21)

An unprecedentedly simple method of synthesis of aryl azides and 3-hydroxytriazenes
Fischer's approach towards the synthesis of aryl azides and triazinoles from diazonium salts and hydroxylammonium chloride (phenylhydraxylamine) was reinvestigated and optimized. The new methodology enables the preparation of aryl azides and triazinoles in high yields in water at room temperature. The procedure is very simple, robust, easily scalable, reproducible, and "green".
Gribanov, Pavel S.,Topchiy, Maxim A.,Golenko, Yulia D.,Lichtenstein, Yana I.,Eshtukov, Artur V.,Terekhov, Vladimir E.,Asachenko, Andrey F.,Nechaev, Mikhail S.
supporting information
p. 5984 - 5988
(2018/06/06)

Photosensitizer-Free Visible-Light-Mediated Gold-Catalyzed 1,2-Difunctionalization of Alkynes
Under visible-light irradiation, the gold-catalyzed intermolecular difunctionalization of alkynes with aryl diazonium salts in methanol affords a variety of α-aryl ketones in moderate to good yields. In contrast to previous reports on gold-catalyzed reactions that involve redox cycles, no external oxidants or photosensitizers are required. The reaction proceeds smoothly under mild reaction conditions and shows broad functional-group tolerance. Further applications of this method demonstrate the general applicability of the arylation of a vinyl gold intermediate instead of the commonly used protodemetalation step. This step provides facile access to functionalized products in one-pot processes. With a P,N-bidentate ligand, a stable aryl gold(III) species was obtained, which constitutes the first direct experimental evidence for the commonly postulated direct oxidative addition of an aryl diazonium salt to a pyridine phosphine gold(I) complex.
Huang, Long,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information
p. 4808 - 4813
(2016/04/19)

Synthesis of 2-aryl-2H-tetrazoles via a regioselective [3+2] cycloaddition reaction
A regioselective cycloaddition reaction of arenediazonium salts with trimethylsilyldiazomethane is reported. A series of 2-aryltetrazoles were obtained in good to moderate yields with wide functional group compatibility. Furthermore, this cycloaddition reaction opens the way to build up the versatile intermediate 2-aryl-5-bromotetrazole.
Patouret, Remi,Kamenecka, Theodore M.
supporting information
p. 1597 - 1599
(2018/03/28)

The promoting effect of pyridine ligands in the Pd-catalysed Heck-Matsuda reaction
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
p. 8855 - 8862
(2016/10/11)

Ligand-Assisted Gold-Catalyzed Cross-Coupling with Aryldiazonium Salts: Redox Gold Catalysis without an External Oxidant
Gold-catalyzed C(sp)-C(sp2) and C(sp2)-C(sp2) cross-coupling reactions are accomplished with aryldiazonium salts as the coupling partner. With the assistance of bpy ligand, gold(I) species were oxidized to gold(III) by diazonium without any external oxidants. Monitoring the reaction with NMR and ESI-MS provided strong evidence for the nitrogen extrusion followed by AuIII reductive elimination as the key step.
Cai, Rong,Lu, Mei,Aguilera, Ellen Y.,Xi, Yumeng,Akhmedov, Novruz G.,Petersen, Jeffrey L.,Chen, Hao,Shi, Xiaodong
supporting information
p. 8772 - 8776
(2015/11/27)

The photoredox-catalyzed meerwein addition reaction: Intermolecular amino-arylation of alkenes
A variety of amides are efficiently accessible under mild conditions by intermolecular amino-arylation using a photo Meerwein addition with visible light. The reaction has a broad substrate scope, tolerates a large range of functional groups, and was applied to the synthesis of a 3-aryl-3,4- dihydroisoquinoline. From elimination to addition: A variety of amides are efficiently accessible under mild conditions by intermolecular amino-arylation using a photo Meerwein addition with visible light. The reaction has a broad substrate scope, tolerates a large range of functional groups, and was applied to the synthesis of 3-aryl-3,4-dihydroisoquinoline. Copyright
Prasad Hari, Durga,Hering, Thea,K?nig, Burkhard
supporting information
p. 725 - 728
(2014/01/23)

Chiral anion phase transfer of aryldiazonium cations: An enantioselective synthesis of C3-diazenated pyrroloindolines
Herein is reported the first asymmetric utilization of aryldiazonium cations as a source of electrophilic nitrogen. This is achieved through a chiral anion phase-transfer pyrroloindolinization reaction that forms C3-diazenated pyrroloindolines from simple tryptamines and aryldiazonium tetrafluoroborates. The title compounds are obtained in up to 99% yield and 96% ee. The air- and water-tolerant reaction allows electronic and steric diversity of the aryldiazonium electrophile and the tryptamine core. Live and let diazene: Chiral anion phase transfer of aryldiazonium cations has been utilized to prepare C3-diazenated pyrroloindolines. The air- and water-tolerant reaction allows electronic and steric diversity in the aryldiazonium electrophile and the tryptamine core, with the products being obtained in up to 99% yield and 96% ee (MTBE=methyl tert-butyl ether).
Nelson, Hosea M.,Reisberg, Solomon H.,Shunatona, Hunter P.,Patel, Jigar S.,Toste, F. Dean
supporting information
p. 5600 - 5603
(2014/06/10)

A simple catalytic system based on PdCl2(CH3CN) 2 in water for cross-coupling reactions using diazonium salts
Aryl-heteroaryl and heteroaryl-heteroaryl compounds are obtained through the Suzuki-Miyaura cross-coupling reactions between diazonium salts and potassium trifluoroborates using PdCl2(CH3CN)2 as the catalyst in water and in the absence of any additive, ligand or base. In addition, the same mild catalytic system is effective for the Matsuda-Heck reaction between several monoolefins with aryldiazonium salts.
El Bakouri, Ouissam,Fernández, Martí,Brun, Sandra,Pla-Quintana, Anna,Roglans, Anna
p. 9761 - 9765
(2013/10/22)

Heck-Matsuda reaction of arenediazonium salts in water
The palladium-catalyzed arylation of alkenes with aryldiazonium salts can be carried out through an environmentally friendly protocol using neat water low palladium loadings at room temperature under base-additive- and ligand-free conditions.
Salabert, Jordi,Sebastián, Rosa María,Vallribera, Adelina,Cívicos, José Francisco,Nájera, Carmen
p. 2655 - 2659
(2013/03/28)

A simple, enaminone-based approach to some bicyclic pyridazinium tetrafluoroborates
Easily obtainable cyclic enaminones (piperidin-2-ylidenealkanones) can be transformed into substituted bicyclic pyridazinium tetrafluoroborates upon treatment with corresponding diazonium salts. The transformation can be performed either in a one-pot way or in a two-step process with the isolation of single azo-coupled enaminone as the intermediate. The former method is superior. Under the optimized conditions, a number of pyridazinium salts substituted with both electron-donating and electron-withdrawing substituents was easily synthesized. A mechanism of the formation of the pyridazinium salts is suggested. A partial drawback is the possibility of the formation of a mixture of products when using a different diazonium salt in each step due to a reversibility of the azo coupling. This can be suppressed by using a more reactive diazonium salt before a less reactive one.
Josefik, Frantisek,Svobodova, Marketa,Bertolasi, Valerio,Simunek, Petr
supporting information
p. 1463 - 1471
(2013/08/23)

A transition-metal-free synthesis of arylcarboxyamides from aryl diazonium salts and isocyanides
A transition-metal-free carboxyamidation process, using aryl diazonium tetrafluoroborates and isocyanides under mild conditions, has been developed. This novel conversion was initiated by a base and solvent induced aryl radical, followed by radical addition to isocyanide and single electron transfer (SET) oxidation, affording the corresponding arylcarboxyamide upon hydration of the nitrilium intermediate.
Xia, Zhonghua,Zhu, Qiang
supporting information
p. 4110 - 4113
(2013/09/12)

Comparative studies on the redox reaction of Fe(CN)6 4-/3- at modified glassy carbon electrodes Via diazonium salts electroreduction
In this paper, the electrochemical properties of glassy carbon (GC) electrodes modified with different functional groups have been investigated. A diazonium salt coupling procedure was used to covalently bind the various p-substituted aryl groups to GC surface. In order to establish suitable grafting conditions enforceable to all kinds of diazonium derivatives, the selection of the molecules to be grafted was done for the contrasted electronegativity of the substituents. We obtained that grafting density could be controlled by varying the concentration of the diazonium, the duration and the value of the applied potential. The surface modification was checked by the blocking action of GC modified electrodes for Fe(CN)63-/4- redox probe in cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements.
Raicopol, Matei,Branzoi, Viorel,Necula, Luiza,Ionita, Mariana,Pilan, Luisa
p. 807 - 814
(2013/05/09)

Electrochemical study on carbon nanotubes functionalization by diazonium salts electroreduction
In this paper, the functionalization of single walled carbon nanotubes (SWCNTs) via electrochemical reduction of aryl diazonium salts in a manner that is similar to the one employed for glassy carbon surfaces is reported. 1-3 The functionalization processes with diazonium salts can lead to further modifications of the nanotubes in order to facilitate their incorporation into polymer composite materials or use in sensors applications. The molecules used for SWCNTs functionalization were chosen for the opposite electronic effects of the aryl substituents and we observed that grafting behaviour depended on the electronic nature of the substituent. The functionalization of SWCNTs was evidenced using voltammetric methods by electrochemical signals related to the immobilized groups in their characteristic potential domain. For electrochemically inactive groups, where it was not possible to evidence the SWCNTs modification by direct electrochemistry methods, the functionalization of SWCNTs was probed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using [Fe(CN)6] 3-/4- as redox marker.
Pilan, Luisa,Raicopol, Matei,Ionita, Mariana,Branzoi, Viorel
p. 815 - 822
(2013/05/22)

Rhodium(I)-catalyzed synthesis of aryltriethoxysilanes from arenediazonium tosylate salts with triethoxysilane
An efficient method for the preparation of aryltriethoxy-silanes from arenediazonium tosylate salts has been developed, which expands the substrates of rhodium-catalyzed silylation from iodides, bromides, and triflates to diazonium salts. A new method for hydrodediazoniation has also been explored.
Tang, Zhi Yong,Zhang, Yuan,Wang, Tao,Wang, Wei
supporting information; experimental part
p. 804 - 808
(2010/06/14)

Electrochemical and impedance spectroscopy studies of various diazonium salts on a glassy carbon electrode
The derivatization of a glassy carbon electrode surface was achieved with and without electrochemical reduction of various diazonium salts in acetonitrile solutions. The surfaces were characterized, before and after their attachment, by cyclic voltammetry and electrochemical impedance spectroscopy to evidence the formation of a coating on the carbon surface. The results were indicative of the presence of substituted phenyl groups on the investigated surface. Also, the effects of diazonium thin films at the surface of a glassy carbon electrode, modification time, and salt concentration on their electrochemical responses in the presence of the Fe(CN)63-/4- probe were investigated. Electrochemical impedance measurements indicated that the kinetics of electron transfer is slowed down when the time and the concentration used to modify the glassy carbon electrode are increased. We therefore modified a glassy carbon surface via its derivatization with and without electrochemical reduction of various diazonium salts in acetonitrile solution. Springer-Verlag 2010.
Khoshroo, Maryam,Rostami, Abbas A.
experimental part
p. 841 - 846
(2011/07/07)

Mechanism of the coupling of diazonium to single-walled carbon nanotubes and its consequences
Due to its simplicity and versatility, diazonium coupling is the most widely used method for carbon nanotube (CNT) functionalization to increase CNT processability and add new functionalities. Yet, its mechanism is so far mostly unknown. Herein, we use kinetic analysis to shed light on this complex mechanism. A free-radical chain reaction is revealed by absorption spectroscopy and ESR. Metallic CNTs are shown to play an unexpected catalytic role. The step determining the selectivity towards metallic CNTs is identified by a Hammett correlation. A mechanistic model is proposed that predicts reactivity and selectivity as a function of diazonium electrophilicity and metallic-to- semiconducting CNT ratio, thus opening perspectives of controlled high-yield functionalization and purification.
Schmidt, Gregory,Gallon, Salome,Esnouf, Stephane,Bourgoin, Jean-Philippe,Chenevier, Pascale
experimental part
p. 2101 - 2110
(2009/09/25)

Halo- and azidodediazoniation of arenediazonium tetrafluoroborates with trimethylsilyl halides and trimethylsilyl azide and Sandmeyer-type bromodediazoniation with Cu(I)Br in [BMIM][PF6] ionic liquid
(Chemical Equation Presented) Reaction of [ArN2][BF4] salts immobilized in [BMIM][PF6] ionic liquid (IL) with TMSX (X = I, Br) and TMSN3 represents an efficient method for the preparation of iodo-, bromo-, and azido-derivatives via dediazoniation. The reactions can also be effected starting with ArNH2 by in situ diazotization with [NO][BF4] followed by reaction with TMSX or TMSN3. Depending on the substituents on the benzenediazonium cation, competing fluorodediazoniation (ArF formation) and hydrodediazoniation (ArH formation) were observed. Dediazoniation with TMSN3 and with TMSI generally gave the highest chemoselectivity toward ArN3 and ArI formation. The IL was recycled and reused up to 5 times with no appreciable decrease in the conversions. Multinuclear NMR monitoring of the interaction of [ArN 2][BF4]/TMSX, [BMIM][PF6]/TMSX, and [BMIM][PF6]/TMSX/[ArN2][BF4] indicated that TMSF is formed primarily via [ArN2][BF4]/ TMSX, generating [ArN2][X] in situ, which gives ArX on dediazoniation. Competing formation of ArF in Sandmeyer-type bromodediazoniation of [ArN 2][BF4] with Cu(I)Br immobilized in the IL points to significant involvement of heterolytic dediazoniation.
Hubbard, Abigail,Okazaki, Takao,Laali, Kenneth K.
p. 316 - 319
(2008/09/17)