- Dihalo(imidazolium)sulfuranes: A Versatile Platform for the Synthesis of New Electrophilic Group-Transfer Reagents
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The syntheses of imidazolium thiocyanates and imidazolium thioalkynes from dihalo(imidazolium) sulfuranes are reported and their reactivities as CN+ and R-CC+ synthons evaluated, respectively. The easy and scalable preparation of these electrophilic reagents, their operationally simple handling, broad substrate scope, and functional group tolerance clearly illustrate the potential of these species to become a reference for the direct electrophilic cyanation and alkynylation of organic substrates.
- Talavera, Garazi,Pe?a, Javier,Alcarazo, Manuel
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- Site-Selective Electrochemical C-H Cyanation of Indoles
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An electrochemical approach for the site-selective C-H cyanation of indoles employing readily available TMSCN as cyano source has been developed. The electrosynthesis relies on the tris(4-bromophenyl)amine as a redox catalyst, which achieves better yield and regioselectivity. A variety of C2- and C3-cyanated indoles were obtained in satisfactory yields. The reactions are conducted in a simple undivided cell at room temperature and obviate the need for transition-metal reagent and chemical oxidant.
- Li, Laiqiang,Hou, Zhong-Wei,Li, Pinhua,Wang, Lei
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supporting information
p. 5983 - 5987
(2021/08/16)
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- DIBENZOTHIOPHENE SALT AS ALKYNYLATING AND CYANATING AGENT
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The present invention describes a new alkynylation and cyanation agent, as well as its preparation and use to introduce nitrile (cyano) or alkyne groups into chemical target molecules by means of an electrophilic reaction. To enable an electrophilic reaction, the chemical backbone of dibenzothiophene was used.
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Paragraph 0098
(2021/08/27)
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- 5-(Cyano)dibenzothiophenium Triflate: A Sulfur-Based Reagent for Electrophilic Cyanation and Cyanocyclizations
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The synthesis of 5-(cyano)dibenzothiophenium triflate 9, prepared by activation of dibenzo[b,d]thiophene-5-oxide with Tf2O and subsequent reaction with TMSCN is reported, and its reactivity as electrophilic cyanation reagent evaluated. The scalable preparation, easy handling and broad substrate scope of the electrophilic cyanation promoted by 9, which includes amines, thiols, silyl enol ethers, alkenes, electron rich (hetero)arenes and polyaromatic hydrocarbons, illustrate the synthetic potential of this reagent. Importantly, Lewis acid activation of the reagent is not required for the transfer process. We additionally report herein biomimetic cyanocyclization cascade reactions, which are not promoted by typical electrophilic cyanation reagents, demonstrating the superior ability of 9 to trigger challenging transformations.
- Li, Xiangdong,Golz, Christopher,Alcarazo, Manuel
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supporting information
p. 9496 - 9500
(2019/06/27)
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- GaCl3-Catalyzed C-H Cyanation of Indoles with N-Cyanosuccinimide
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An efficient GaCl3-catalyzed direct cyanation of indoles and pyrroles using bench-stable electrophilic cyanating agent N-cyanosuccinimide was achieved and afforded 3-cyanoindoles and 2-cyanopyrroles in good yields and excellent regioselectivities. Notably, this protocol exhibited high reactivity for unprotected indoles and was applicable to a broad range of indole and pyrrole substrates.
- Wang, Xue,Makha, Mohamed,Chen, Shu-Wei,Zheng, Huaiji,Li, Yuehui
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p. 6199 - 6206
(2019/05/24)
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- Palladium-Catalyzed Late-Stage Direct Arene Cyanation
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Methods for direct benzonitrile synthesis are sparse, despite the versatility of cyano groups in organic synthesis and the importance of benzonitriles for the dye, agrochemical, and pharmaceutical industries. We report the first general late-stage aryl C–H cyanation with broad substrate scope and functional-group tolerance. The reaction is enabled by a dual-ligand combination of quinoxaline and an amino acid-derived ligand. The method is applicable to direct cyanation of several marketed small-molecule drugs, common pharmacophores, and organic dyes. Benzonitriles are some of the most versatile building blocks for organic synthesis, in particular in the pharmaceutical industry, but general methods to make them by direct C–H functionalization are unknown. In this issue of Chem, Ritter and coworkers describe a late-stage aryl C–H cyanation with broad substrate scope and functional-group tolerance, enabled by a palladium-dual-ligand catalyst system. The reaction may serve for the late-stage modification of drug candidates. Aryl nitriles constitute an important class of organic compounds that are widely found in natural products, pharmaceuticals, agricultural chemicals, dyes, and materials. Moreover, nitriles are versatile building blocks to access numerous other important molecular structure groups. However, no general method for direct aromatic C–H cyanation is known. All approaches to date require either an appropriate directing group or reactive electron-rich substrates, such as indoles, which limit their synthetic applications. Here we describe an undirected, palladium-catalyzed late-stage aryl C–H cyanation reaction for the synthesis of complex aryl nitriles that would otherwise be more challenging to produce. The wide substrate scope and good functional-group tolerance of this reaction provide direct and quick access to structural diversity for pharmaceutical and agrochemical development.
- Zhao, Da,Xu, Peng,Ritter, Tobias
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supporting information
p. 97 - 107
(2019/01/21)
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- An insight on the influence of surface Lewis acid sites for regioselective C–H bond C3-cyanation of indole using NH4I and DMF as combined cyanide source over Cu/SBA-15 catalyst
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The Cu dispersed on mesoporous SBA-15 has demonstrated the regioselective C–H bond C3-cyanation of indoles by in-situ generation of –CN using DMF and NH4I in presence of O2. Pyridine adsorbed diffuse reflectance infrared spectroscopy (DRIFTS) results revealed that surface Cu2+ species are acting as Lewis acid sites in the in-situ generation of cyano- group for the synthesis of indole nitriles. A direct correlation between Cu metal surface area and the indole nitrile yields are established and the dual role of copper is substantiated by N2O titration and XPS techniques. The 10 wt%Cu/SBA-15 demonstrated superior performance when compared to Pd, Ru supported on SBA-15. The 10 wt%Cu/SBA-15 catalyst showed consistent activity and selectivity after the 4th cycle.
- Boosa, Venu,Bilakanti, Vishali,Velisoju, Vijay Kumar,Gutta, Naresh,Inkollu, Sreedhar,Akula, Venugopal
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- Copper-Catalyzed Acyloxycyanation of Alkynes with Acetonitrile: Regioselective Construction of Cyclic Acrylonitriles by 6-endo or 5-exo Cyclization
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An efficient difunctionalization of alkynes by tandem iodolactonization and copper-catalyzed cyanation using acetonitrile as a cyanating reagent is reported for the first time. This approach can afford cyano-containing isocoumarin or phthalide derivatives
- Zhu, Yamin,Shen, Zengming
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supporting information
p. 3515 - 3519
(2017/09/13)
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- SUBSTITUTED IMIDAZOLIUM SULFURANES AND THEIR USE
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The present invention refers to substituted imidazolium sulfuranes, the use thereof for the transfer of a -CN group or an alkyne group.
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Page/Page column 17; 18
(2017/01/26)
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- A facile and efficient synthesis of 3-cyanoindoles by a simple palladium(II)-catalyzed C─H activation of indoles
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An efficient trans-PdCl2(NH2CH2COOH)2-catalyzed direct C3-cyanation of indole C─H bonds is described. Notably, free (N─H)-indoles reacted smoothly using the procedure, and the desired product 3-cyanoindoles were obtained in good to excellent yields.
- Chu, Hailiang,Guo, Mengping,Yi, Yanping,Wen, Yongju,Zhou, Lanjiang,Huang, Hongwei
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- Cu-Catalyzed Cyanation of Indoles with Acetonitrile as a Cyano Source
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Cu-catalyzed cyanation of indoles with acetonitrile for the synthesis of 3-cyanoindoles has been developed. The Cu/TEMPO/(Me3Si)2 system has been identified to promote highly efficient and selective C-H cyanation of indoles by use of unactivated acetonitrile as a cyano source via a sequential iodination/cyanation process in one pot. This reaction furnishes 3-cyanoindoles in moderate to good yields and tolerates a series of functional groups. Moreover, low-cost copper catalysts and hazardless acetonitrile as a cyano source feature the practicability of this reaction.
- Zhao, Mengdi,Zhang, Wei,Shen, Zengming
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p. 8868 - 8873
(2015/09/15)
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- Selective synthesis of indazoles and indoles via triazene-alkyne cyclization switched by different metals
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We described two orthogonal heterocycle syntheses, where an arene bearing both an alkyne and a triazene functionality underwent two distinct cyclization pathways mediated by different transition metals. Starting from the same substrates, a synthesis of 2H
- Fang, Yan,Wang, Chengming,Su, Shengqin,Yu, Haizhu,Huang, Yong
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p. 1061 - 1071
(2014/02/14)
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- Zinc-catalyzed direct cyanation of indoles and pyrroles: Nitromethane as a source of a cyano group
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With nitromethane and diphenylsilane (Ph2SiH2), zinc triflate behaves as a Lewis acid catalyst for the cyanation of nitrogen-containing heteroarenes such as indoles and pyrroles. This is the first realization of the Lewis acid-catalyzed direct cyanation of a C(aryl)-H bond with no CN group-containing cyanating agent.
- Nagase, Yuta,Sugiyama, Tetsuya,Nomiyama, Shota,Yonekura, Kyohei,Tsuchimoto, Teruhisa
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supporting information
p. 347 - 352
(2014/05/20)
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- Copper-mediated C3-cyanation of indoles by the combination of amine and ammonium
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A copper-promoted C3-cyanation of both the free N-H and N-protected indoles by N,N,N′,N′-tetramethyl-ethane-1,2-diamine (TMEDA) and ammonium is achieved. The iminium ion acts as the intermediate in this transformation, which is sequentially electrophilically attacked by indole and H2O followed by hydrolyzation to form the aldehyde. Then the reaction between the aldehyde and ammonium afforded nitriles. The reaction employs O2 as a clean oxidant with good efficiency and functional group tolerance. Thus, it represents a facile and safe procedure leading to 3-cyano indoles. The Royal Society of Chemistry 2014.
- Liu, Bin,Wang, Jiehui,Zhang, Bo,Sun, Yang,Wang, Lei,Chen, Jianbin,Cheng, Jiang
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supporting information
p. 2315 - 2317
(2014/03/21)
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- Switchable synthesis of 3-cyanoindoles and 3-amidylindoles via a palladium-catalyzed reaction of N,N-dimethyl-2-alkynylaniline with isocyanide
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A palladium-catalyzed reaction of N,N-dimethyl-2-alkynylanilines with isocyanides is reported, leading to the formation of 3-cyanoindoles and 3-amidylindoles. The isocyanide insertion is the key step during the process, and the presence of water is essential for the formation of 3-amidylindoles.
- Qiu, Guanyinsheng,Qiu, Xiaochen,Liu, Jianping,Wu, Jie
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supporting information
p. 2441 - 2446
(2013/10/01)
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- Cyanation of indoles with benzyl cyanide as the cyanide anion surrogate
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A copper-mediated direct cyanation of indoles with benzyl cyanide as the cyanide anion surrogate has been achieved. The cascade reaction furnished 3-cyanoindoles under mild reaction conditions in good to excellent yields with various functional groups tolerance.
- Zhang, Lianpeng,Wen, Qiaodong,Jin, Jisong,Wang, Chen,Lu, Ping,Wang, Yanguang
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p. 4236 - 4240
(2013/06/26)
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- Synthesis of 3-cyanoindole derivatives mediated by copper(I) iodide using benzyl cyanide
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Copper-mediated direct and regioselective C3-cyanation of indoles using benzyl cyanide as the cyanide anion source is presented. A wide range of indoles undergo cyanation smoothly by employing a reaction system of copper(I) iodide under open-to-air vessels.
- Yuen, On Ying,Choy, Pui Ying,Chow, Wing Kin,Wong, Wing Tak,Kwong, Fuk Yee
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p. 3374 - 3378
(2013/06/26)
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- Copper-mediated selective cyanation of indoles and 2-phenylpyridines with ammonium iodide and DMF
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Copper-mediated regioselective cyanation of indoles and 2-phenylpyridines was developed by using ammonium iodide and DMF as the combined source of a cyano unit under Pd-free conditions. Mechanistic studies indicate that the reaction of indoles proceeds through a two-step sequence: electrophilic initial iodination and then cyanation. The cyanation has a broad substrate scope, high functional group tolerance, and excellent regioselectivity.
- Kim, Jinho,Kim, Hyunwoo,Chang, Sukbok
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supporting information; experimental part
p. 3924 - 3927
(2012/09/21)
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- Iron-mediated cyanation of methoxybenzene, indole, and 2-arylpyridine C-H bonds
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An iron-mediated direct cyanation of indole and 2-arylpyridine C-H bonds is described. Notably, trimethoxybenzene reacted smoothly under the procedure, forming a C-CN bond via C-H bond cleavage without chelation assistance. Georg Thieme Verlag Stuttgart · New York.
- Zhang, Guangyou,Lv, Guanglei,Pan, Changduo,Cheng, Jiang,Chen, Fan
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supporting information; experimental part
p. 2991 - 2994
(2012/01/07)
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- Lewis acid catalyzed direct cyanation of indoles and pyrroles with N-cyano-N-phenyl-p-toluenesulfonamide (NCTS)
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BF3?OEt2-catalyzed direct cyanation of indoles and pyrroles using a less toxic, bench-stable, and easily handled electrophilic cyanating agent N-cyano-N-phenyl-para-toluenesulfonamide (NCTS) affords 3-cyanoindoles and 2-cyanopyrroles in good yields with excellent regioselectivity. The substrate scope is broad with respect to indoles and pyrroles.
- Yang, Yang,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 5608 - 5611
(2011/12/03)
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- Direct transformation of N, N -dimethylformamide to -CN: Pd-catalyzed cyanation of heteroarenes via C-H functionalization
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This paper describes the direct cyanation of indoles and benzofurans employing N,N-dimethylformamide (DMF) as both reagent and solvent. Isotopic labeling experiments indicated that both the N and the C of the cyano group derived from DMF. This transformation offers an alternative method for preparing aryl nitriles, though it is currently limited in scope to indoles and benzofurans.
- Ding, Shengtao,Jiao, Ning
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p. 12374 - 12377
(2011/10/02)
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- The palladium-catalyzed cyanation of indole C-H bonds with the combination of NH4HCO3 and DMSO as a safe cyanide source
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A palladium-catalyzed cyanation of the 3-position of indole sp2 C-H bonds by the combination of NH4HCO3 and DMSO as the "CN" source was achieved to provide aromatic nitriles in moderate to good yields with excellent regioselectivity. It represents a practical and safe cyanation method.
- Ren, Xinyi,Chen, Jianbin,Chen, Fan,Cheng, Jiang
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experimental part
p. 6725 - 6727
(2011/07/07)
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- Palladium-catalyzed direct cyanation of indoles with K4[Fe(CN) 6]
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"Chemical equation presented" Direct cyanation of Indole derivatives has been achieved with nontoxic K4[Fe(CN)6] as cyanating agent through Pd-catalyzed C-H bond activation.
- Yan, Guobing,Kuang, Chunxiang,Zhang, Yan,Wang, Jianbo
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scheme or table
p. 1052 - 1055
(2010/06/13)
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- Heterocyclic Rearrangements. Phenylhydrazones and N-Methyl-N-phenylhydrazones of 3-Acylisoxazoles
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The reaction of 3-benzoyl-5-phenylisoxazole (4) and 3-acetyl-5-methylisoxazole (5) with phenylhydrazine and N-methyl-N-phenylhydrazine has been investigated and the reactivity of (E)- and (Z)-phenylhydrazones and N-methyl-N-phenylhydrazones has been studied.
- Vivona, Nicolo,Macaluso, Gabriella,Frenna, Vincenzo,Ruccia, Michele
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p. 931 - 934
(2007/10/02)
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