4282-47-7Relevant academic research and scientific papers
Three-Component Couplings among Heteroarenes, Difluorocyclopropenes, and Water via C-H Activation
Liu, Xuexin,Chen, Jian,Yang, Chunyan,Wu, Zhouping,Li, Zhiyang,Shi, Yuesen,Huang, Tianle,Yang, Zhongzhen,Wu, Yong
supporting information, p. 6831 - 6835 (2021/09/08)
Three-component couplings have been realized for efficiently constructing various nitrogen-containing skeletons via C-H activation, where difluorocyclopropenes have been first identified as coupling partners. Many substrates including sp2 and sp3 C-H substrates were well tolerated, furnishing the corresponding products in good yields. Furthermore, a catalyst-dependent reaction was also developed, enabling divergent construction of two different frameworks. The application value of these reactions was demonstrated in gram-scale experiments with as little as 1 mol % catalyst.
Photoarylation of Pyridines Using Aryldiazonium Salts and Visible Light: An EDA Approach
Bartolomeu, Aloisio De A.,Brocksom, Timothy J.,De Oliveira, Kleber T.,No?l, Timothy,Silva, Rodrigo C.
, (2019/08/26)
A metal-free methodology for the photoarylation of pyridines, in water, is described giving 2 and 4-arylated-pyridines in yields up to 96percent. The scope of the aryldiazonium salts is presented showing important results depending on the nature and position of the substituent group in the diazonium salt, that is, electron-donating or electron-withdrawing in the ortho, meta, or para positions. Further heteroaromatics were also successfully photoarylated. Mechanistic studies and comparison between our methodology and similar metal-catalyzed procedures are presented, suggesting the occurrence of a visible-light EDA complex which generates the aryl radical with no need for an additional photocatalyst.
Synthesis, structure, and synthetic potential of arenediazonium trifluoromethanesulfonates as stable and safe diazonium salts
Filimonov, Victor D.,Krasnokutskaya, Elena A.,Kassanova, Assia Zh.,Fedorova, Valentina A.,Stankevich, Ksenia S.,Naumov, Nikolay G.,Bondarev, Alexander A.,Kataeva, Veronika A.
supporting information, p. 665 - 674 (2018/09/14)
Aromatic diazonium salts are valuable building blocks for organic synthesis; however, in most cases, they are unstable, unsafe, poorly soluble, and/or expensive. In this paper, we have shown that a variety of stable and safe arenediazonium triflates ArN2+ TfO– can be obtained easily and in high yields by diazotization of anilines with tert-butyl nitrite in the presence of trifluoromethanesulfonic acid. Arenediazonium triflates are relatively shelf-stable in the dry state. They dissolve well in water, as well as polar and even nonpolar organic solvents. Less than 800 J/g of energy is released during the thermal decomposition of these salts, which indicates their explosion safety. Arenediazonium triflates have a high reactivity in the known reactions of diazonium chemistry, and undergo an unusual metal-free chlorodediazonization reaction with chloroform and CCl4.
A tetranuclear CuII2DyIII2 coordination cluster as a Suzuki (C-C) coupling reaction promoter
Kumar, Prashant,Griffiths, Kieran,Anson, Christopher E.,Powell, Annie K.,Kostakis, George E.
supporting information, p. 17202 - 17205 (2019/01/03)
The air-stable tetranuclear coordination cluster [CuII2DyIII2L4(NO3)2(CH3CN)2]·2(CH3CN), which can be obtained in high yield, promotes the Suzuki coupling reaction of phenylboronic acid with substituted aryl halides under environmentally benign conditions.
C6-Selective Direct Arylation of 2-Phenylpyridine via an Activated N-methylpyridinium Salt: A Combined Experimental and Theoretical Study
Yin, Changzhen,Zhong, Kangbao,Li, Wenjing,Yang, Xiao,Sun, Rui,Zhang, Chunchun,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Lan, Yu,Fu, Haiyan,Chen, Hua
supporting information, p. 3990 - 3998 (2018/09/12)
An elegant pre-activation strategy, based on the formation of N-methylpyridinium iodide salts for C6-selective direct arylation of 2-phenylpyridines using Pd/Cu cooperative catalysis, has been developed. By this methodology, a wide range of unsymmetrical 2, 6-diarylpyridines were synthesized with high reactivity and regioselectivity as well as good functional group tolerance. In particular, challenging substrates bearing electron donating groups (EDGs), such as OMe, NMe2, were also successfully employed in this reaction. Deuterium incorporation studies revealed that the C?H bond acidity is improved significantly in N-methylpyridinium salts compared with their N-Oxide and N-iminopyridinium ylide counterparts, thus solving the long-standing problem associated with previous strategies for the synthesis of diaryl pyridines. Finally, the control experiments and DFT calculations supported a Pd-catalyzed and Cu-mediated mechanism in which a carbenoid copper species that is formed in-situ from N-methylpyridinium salts, participates in a Pd-catalyzed arylation followed by an iodide-promoted N-demethylation process. (Figure presented.).
Synthesis of Bi(hetero)aryls via Sequential Oxidation and Decarboxylation of Benzylamines in a Batch/Fully Automated Continuous Flow Process
Mahajan, Bhushan,Aand, Dnyaneshwar,Singh, Ajay K.
supporting information, p. 2831 - 2835 (2018/06/21)
Catalytic dehydrogenative cross-coupling of two C–H bonds represents a green strategy in view of the atom- and step-economy. However, the challenge is to discover a new innovative bond strategy, especially for the direct coupling between Csp2–H
An Iron-Based Long-Lived Catalyst for Direct C?H Arylation of Arenes and Heteroarenes
Chakraborty, Soumi,Ahmed, Jasimuddin,Shaw, Bikash Kumar,Jose, Anex,Mandal, Swadhin K.
, p. 17651 - 17655 (2018/11/10)
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.
Visible-Light-Promoted Arylation Reactions Photocatalyzed by Bismuth(III) Oxide
Buglioni, Laura,Riente, Paola,Palomares, Emilio,Pericàs, Miquel A.
supporting information, p. 6986 - 6990 (2017/12/26)
Bismuth(III) oxide has been successfully applied as a photocatalyst in the arylation of heteroarenes with diazonium salts. With a low catalyst loading (1 to 5 mol-%), this cheap and nontoxic semiconductor could efficiently promote the formation of the aryl radical under visible light irradiation. The arylated products are obtained in moderate to good yields, and the process admits straightforward scale-up (10 mmol; 1 mol-% Bi2O3). In two cases, the diazonium salt was generated in situ and used in the photocatalytic arylation in a tandem manner. Besides heteroarenes, Bi2O3 also catalyzed the arylation of differently substituted alkenes and alkynes, thus representing a viable and practical alternative to the more commonly used ruthenium complexes and organic dyes.
Blue light mediated C-H arylation of heteroarenes using TiO2 as an immobilized photocatalyst in a continuous-flow microreactor
Fabry, David C.,Ho, Yee Ann,Zapf, Ralf,Tremel, Wolfgang,Panth?fer, Martin,Rueping, Magnus,Rehm, Thomas H.
supporting information, p. 1911 - 1918 (2017/06/09)
Titanium dioxide was applied as an immobilized photocatalyst in a microstructured falling film reactor for the continuous-flow C-H arylation of heteroarenes with aryldiazonium salts as the starting material. Detailed investigations of the catalyst and a successful long-term run proved its excellent usability for this process. Very good yields up to 99% were achieved with broad substrate scope and were compared with batch synthesis. The transfer to the continuous-flow mode revealed an impressive boost in reactor performance solely resulting from the improved irradiation and contact of the catalyst, substrate and light.
A new face of phenalenyl-based radicals in the transition metal-free C-H arylation of heteroarenes at room temperature: Trapping the radical initiator: Via C-C σ-bond formation
Ahmed, Jasimuddin,Sreejyothi,Vijaykumar, Gonela,Jose, Anex,Raj, Manthan,Mandal, Swadhin K.
, p. 7798 - 7806 (2017/10/30)
The radical-mediated transition metal-free approach for the direct C-H bond functionalization of arenes is considered as a cost effective alternative to transition metal-based catalysis. An organic ligand-based radical plays a key role by generating an aryl radical which undergoes a subsequent functionalization process. The design principle of the present study takes advantage of a relatively stable odd alternant hydrocarbon-based phenalenyl (PLY) radical. In this study, the first transition metal-free catalyzed direct C-H arylation of a variety of heteroarenes such as azoles, furan, thiophene and pyridine at room temperature has been reported using a phenalenyl-based radical without employing any photoactivation step. This protocol has been successfully applied to the gram scale synthesis of core moieties of bioactive molecules. The phenalenyl-based radical initiator has been characterized crystallographically by trapping it via the formation of a C-C σ-bond between the phenalenyl radical and solvent-based radical species.
