- A mechanistic study on modern palladium catalyst precursors as new gateways to Pd(0) in cationic Heck reactions
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Electrospray ionization mass spectrometry (ESI-MS) was used as a means to directly identify catalytic cationic organopalladium species in ligand-controlled Heck reactions involving electron-rich olefins and different Pd-sources. In these high-temperature Heck arylations, the oxidative addition intermediates were observed as bidentate ligand chelated cationic aryl palladium species, suggesting that the used ligand attaches to the metal center at the very beginning of the catalytic cycle. This was also in agreement with the obtained regioisomeric profile of the isolated products. The investigation supports the standard Pd(0)/Pd(II) Heck mechanism and provides further insight regarding the conceivable composition of fundamental Pd(II) intermediates in an ongoing Heck reaction.
- Svennebring, Andreas,Sj?berg, Per J.R.,Larhed, Mats,Nilsson, Peter
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Read Online
- Copper-catalyzed cyanation of aryl iodide with the combined cyanide source of urea and DMSO
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A simple copper-catalyzed cyanation of aryl iodide with the combination of urea and dimethyl sulfoxide as a cyanide source is achieved, providing nitriles in moderate to good yields. This new approach represents an exceedingly practical and safe method for the synthesis of aryl nitriles.
- Zheng, Kui,Liu, Bin,Chen, Shuyou,Chen, Fan
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Read Online
- Copper- and silver-mediated cyanation of aryl iodides using ddq as cyanide source
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A new copper and silver-mediated cyanation of aryl iodides with DDQ as a cyanide source is achieved, providing nitriles with good yields. This new approach represents a safe method leading to aryl nitriles. A new copper and silver-mediated cyanation of aryl iodides with DDQ as a cyanide source is achieved.
- Zheng, Kui,Yu, Peng,Chen, Shuyou,Chen, Fen,Cheng, Jiang
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Read Online
- Optimisation and scale-up of microwave assisted cyanation
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A microwave enhanced palladium catalysed cyanation procedure was optimised for the final step of a production method for citalopram 2. The method was demonstrated on multigram batch scale for the synthesis of escitalopram (S)-2 and then in a stop-flow continuous process for citalopram.
- Pitts, Michael R.,McCormack, Peter,Whittall, John
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Read Online
- Palladium-catalyzed cyanation of aryl halides using K4[Fe(CN)6] as cyanide source, water as solvent, and microwave heating
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A methodology for the cyanation of aryl iodides and activated aryl bromides is reported using water as the solvent and K4[Fe(CN)6] as the cyanide source. Reactions are complete within 20 min.
- Velmathi, Sivan,Leadbeater, Nicholas E.
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Read Online
- Visible light-mediated, high-efficiency oxidation of benzyl to acetophenone catalyzed by fluorescein
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An environmentally friendly aerobic oxidation of benzyl C(sp3)-H bonds to ketones via selective oxidation catalysis was developed. Fluorescein is an efficient photocatalyst with excellent chemical selectivity. The reaction has a wide substrate scope, and a successful gram-scale experiment demonstrated its potential industrial utility.
- Geng, Haoxing,Liu, Xin,Zhu, Qing
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supporting information
(2021/12/20)
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- Recyclable and Reusable Pd(OAc)2/XPhos–SO3Na/PEG-400/H2O System for Cyanation of Aryl Chlorides with Potassium Ferrocyanide
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Pd(OAc)2/XPhos–SO3Na in a mixture of poly(ethylene glycol) (PEG-400) and water is shown to be a highly efficient catalyst for the cyanation of aryl chlorides with potassium ferrocyanide. The reaction proceeded smoothly at 100 or 120?oC with K2CO3 or KOAc as base, delivering a variety of aromatic nitriles in good to excellent yields. The isolation of the crude products is facilely performed by extraction with cyclohexane and more importantly, both expensive Pd(OAc)2 and XPhos–SO3Na in PEG-400/H2O system could be easily recycled and reused at least six times without any apparent loss of catalytic efficiency. Graphical Abstract: Palladium-catalyzed cyanation of aryl chlorides with potassium ferrocyanide leading to aryl nitriles by using Pd(OAc)2/XPhos–SO3Na/PEG-400/H2O as a highly efficient and recyclable catalytic system is described.[Figure not available: see fulltext.]
- Cai, Mingzhong,Huang, Bin,Liu, Rong,Xu, Caifeng
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- Pd@CeO2-catalyzed cyanation of aryl iodides with K4Fe(CN)6·3H2O under visible light irradiation
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Cyanation of aryl iodides is still challenging work for chemical researchers because of harsh reaction conditions and toxic cyanide sources. Herein, we have developed a new protocol based on the combination of the catalyst Pd@CeO2, nontoxic cyanide source K4[Fe (CN)6]·3H2O, and driving force visible light irradiation. The reaction is operated at relatively moderate temperature (55°C) and exhibits good catalytic efficiency of product aryl nitriles (yields of 89.4%). Moreover, the catalyst Pd@CeO2 possesses good reusability with a slight loss of photocatalytic activity after five consecutive runs. The reaction system based on the above combination shows a wide range of functional group tolerance under the same conditions. Reaction conditions such as temperature, time, the component of catalyst, and solutions are optimized by studying cyanation of 1-iodo-4-nitrobenzene as model reaction. According to these results, the possible mechanism of Pd@CeO2-catalyzed cyanation of aryl iodides under visible light irradiation is proposed based on the influence of visible light on the catalyst and reactant compounds. In all, we provided an environmental and economic method for preparation of aryl nitriles from cyanation of aryl iodides based on the goal of green chemistry for sustainable development.
- Wang, Shengyu,Wang, Jianqiang,Pan, Junyi,Liu, Cheng,Gong, Xubin,Guo, Cheng
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- o-Quinone methide with overcrowded olefin component as a dehydridation catalyst under aerobic photoirradiation conditions
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Ano-quinone methide (o-QM) featuring an overcrowded olefinic framework is introduced, which exhibits dehydridation activity owing to its enhanced zwitterionic character, particularly through photoexcitation. The characteristics of thiso-QM enable the operation of dehydridative catalysis in the oxidation of benzylic secondary alcohols under aerobic photoirradiation conditions. An experimental analysis and density functional theory calculations provide mechanistic insights; the ground-state zwitterionic intermediate abstracts a hydride and proton simultaneously, and the active oxygen species facilitate catalyst regeneration.
- Uraguchi, Daisuke,Kato, Kohsuke,Ooi, Takashi
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p. 2778 - 2783
(2021/03/14)
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- SBA-15 Supported 1-Methyl-2-azaadamanane N-Oxyl (1-Me-AZADO) as Recyclable Catalyst for Oxidation of Alcohol
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Herein, we designed and synthesized an SBA-15 supported 1-methyl-2-azaadamanane N-oxyl (1-Me-AZADO) and investigated its catalytic performance for selective oxidation of alcohols under Anelli's conditions. The first example of immobilization of 1-Me-AZADO was very important to advance the oxgenation effectively because this supported N-oxyl has excellent catalytic activity for oxidation of alcohols to carbonyl compounds, and more importantly, it can be conveniently recovered and reused at least 6 times without significant effect on its catalytic efficiency.
- Tian, Yangwu,Guo, Xiaqun,Li, Meichao,Li, Chunmei,Hu, Xinquan,Jin, Liqun,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu
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supporting information
p. 3928 - 3932
(2021/05/26)
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- Promoting charge separation in donor-acceptor conjugated microporous polymers: Via cyanation for the photocatalytic reductive dehalogenation of chlorides
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Conjugated microporous polymers (CMPs) have emerged as promising heterogeneous photocatalysts for organic transformations owing to their structural designability and functional versatility. However, limited by the insufficient separation of the photo-generated excitons, their photocatalytic efficiency falls far short of expectations. Herein, we demonstrate a cyanation strategy to promote charge carrier separation in CMPs by selectively incorporating carbazole and cyano groups as electron-donating and electron-withdrawing units, respectively. The resulting CMPs feature π-extended donor (D)-acceptor (A) conjugation structures endowing them with distinct semiconducting properties, in which the efficient charge separation and transfer and wide visible-light absorption are facilitated. Compared to the cyano-free counterpart, the cyano-functionalized CMPs showed superior photocatalytic efficiency as exemplified by photocatalytic reductive dehalogenation of chlorides. More prominently, full recyclability of the designed CMPs as well as catalytic activity for at least ten runs without the loss of catalytic performance in photocatalytic reductive dehalogenation of chlorides demonstrated their robustness and sustainability. This journal is
- Deng, Jiyong,Fang, Zhengjun,Lan, Donghui,Liao, Yunfeng,Liu, Qingquan,Zhang, Weijie,Zhou, Xiang
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p. 7151 - 7159
(2021/11/17)
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- Nickel-Catalyzed Cyanation of Aryl Thioethers
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A nickel-catalyzed cyanation of aryl thioethers using Zn(CN)2 as a cyanide source has been developed to access functionalized aryl nitriles. The ligand dcype (1,2-bis(dicyclohexylphosphino)ethane) in combination with the base KOAc (potassium acetate) is essential for achieving this transformation efficiently. This reaction involves both a C-S bond activation and a C-C bond formation. The scalability, low catalyst and reagents loadings, and high functional group tolerance have enabled both late-stage derivatization and polymer recycling, demonstrating the reaction's utility across organic chemistry.
- Delcaillau, Tristan,Woenckhaus-Alvarez, Adrian,Morandi, Bill
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supporting information
p. 7018 - 7022
(2021/09/13)
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- Photoinduced Acetylation of Anilines under Aqueous and Catalyst-Free Conditions
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A green and efficient visible-light induced functionalization of anilines under mild conditions has been reported. Utilizing nontoxic, cost-effective, and water-soluble diacetyl as photosensitizer and acetylating reagent, and water as the solvent, a variety of anilines were converted into the corresponding aryl ketones, iodides, and bromides. With advantages of environmentally friendly conditions, simple operation, broad substrate scope, and functional group tolerance, this reaction represents a valuable method in organic synthesis.
- Yang, Yu-Ming,Yan, Wei,Hu, Han-Wei,Luo, Yimin,Tang, Zhen-Yu,Luo, Zhuangzhu
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p. 12344 - 12353
(2021/09/02)
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- Regioselective mercury(I)/palladium(II)-catalyzed single-step approach for the synthesis of imines and 2-substituted indoles
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An efficient synthesis of ketimines was achieved through a regioselective Hg(I)-catalyzed hydroamination of terminal acetylenes in the presence of anilines. The Pd(II)-catalyzed cycliza-tion of these imines into the 2-substituted indoles was satisfactorily carried out by a C-H acti-vation. In a single-step approach, a variety of 2-substituted indoles were also generated via a Hg(I)/Pd(II)-catalyzed, one-pot, two-step process, starting from anilines and terminal acetylenes. The arylacetylenes proved to be more effective than the alkyl derivatives.
- Delgado, Francisco,Gutiérrez, Rsuini U.,Hernández-Montes, Mayra,Mendieta-Moctezuma, Aarón,Tamariz, Joaquín
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- Copper-promoted cyanation of aryl iodides with N,N-dimethyl aminomalononitrile
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A copper-promoted cyanation of aryl iodides has been successfully developed by using N,N-dimethyl aminomalononitrile as the cyanide source with moderate toxicity and better stability. This reaction features broad substrate scope, excellent reaction yields, readily available catalyst, and simple reaction conditions.
- Liu, Si-Zhan,Li, Jing,Xue, Cao-Gen,Xu, Xue-Tao,Lei, Lin-Sheng,Huo, Chen-Yu,Wang, Zhen,Wang, Shao-Hua
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supporting information
(2021/02/01)
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- Facile dehydration of primary amides to nitriles catalyzed by lead salts: The anionic ligand matters
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The synthesis of nitrile under mild conditions was achieved via dehydration of primary amide using lead salts as catalyst. The reaction processes were intensified by not only adding surfactant but also continuously removing the only by-product, water from the system. Both aliphatic and aromatic nitriles can be prepared in this manner with moderate to excellent yields. The reaction mechanisms were obtained with high-level quantum chemical calculations, and the crucial role the anionic ligand plays in the transformations were revealed.
- Ruan, Shixiang,Ruan, Jiancheng,Chen, Xinzhi,Zhou, Shaodong
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- Organotellurium-catalyzed oxidative deoximation reactions using visible-light as the precise driving energy
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Irradiated by visible light, the recyclable (PhTe)2-catalyzed oxidative deoximation reaction could occur under mild conditions. In comparison with the thermo reaction, the method employed reduced catalyst loading (1 mol% vs. 2.5 mol%), but afforded elevated product yields with expanded substrate scope. This work demonstrated that for the organotellurium-catalyzed reactions, visible light might be an even more precise driving energy than heating because it could break the Te–Te bond accurately to generate the active free radical catalytic intermediates without damaging the fragile substituents (e.g., heterocycles) of substrates. The use of O2 instead of explosive H2O2 as oxidant affords safer reaction conditions from the large-scale application viewpoint.
- Deng, Xin,Qian, Rongrong,Zhou, Hongwei,Yu, Lei
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supporting information
p. 1029 - 1032
(2020/10/23)
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- Surface Coordination of Multiple Ligands Endows N-Heterocyclic Carbene-Stabilized Gold Nanoclusters with High Robustness and Surface Reactivity
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Deciphering the molecular pictures of the multi-component and non-periodic organic-inorganic interlayer is a grand technical challenge. Here we show that the atomic arrangement of hybrid surface ligands on metal nanoparticles can be precisely quantified through comprehensive characterization of a novel gold cluster, Au44(iPr2-bimy)9(PA)6Br8 (1), which features three types of ligands, namely, carbene (1,3-diisopropylbenzimidazolin-2-ylidene, iPr2-bimy), alkynyl (phenylacetylide, PA), and halide (Br), respectively. The delicately balanced stereochemical effects and bonding capabilities of the three ligands give rise to peculiar geometrical and electronic structures. Remarkably, despite its complex and highly distorted surface structure, cluster 1 exhibits unusual catalytic properties and yet it is highly stable, both chemically and thermally. Moreover, rich reactive sites on the cluster surface raise the prospect of bio-compatibility (as it can be functionalized to yield water-soluble derivatives) and bio-applications.
- Shen, Hui,Xu, Zhen,Hazer, Maryam Sabooni Asre,Wu, Qingyuan,Peng, Jian,Qin, Ruixuan,Malola, Sami,Teo, Boon K.,H?kkinen, Hannu,Zheng, Nanfeng
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supporting information
p. 3752 - 3758
(2020/12/17)
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- A Molecular Iron-Based System for Divergent Bond Activation: Controlling the Reactivity of Aldehydes
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The direct synthesis of amides and nitriles from readily available aldehyde precursors provides access to functional groups of major synthetic utility. To date, most reliable catalytic methods have typically been optimized to supply one product exclusively. Herein, we describe an approach centered on an operationally simple iron-based system that, depending on the reaction conditions, selectively addresses either the C=O or C-H bond of aldehydes. This way, two divergent reaction pathways can be opened to furnish both products in high yields and selectivities under mild reaction conditions. The catalyst system takes advantage of iron's dual reactivity capable of acting as (1) a Lewis acid and (2) a nitrene transfer platform to govern the aldehyde building block. The present transformation offers a rare control over the selectivity on the basis of the iron system's ionic nature. This approach expands the repertoire of protocols for amide and nitrile synthesis and shows that fine adjustments of the catalyst system's molecular environment can supply control over bond activation processes, thus providing easy access to various products from primary building blocks.
- Chatterjee, Basujit,Jena, Soumyashree,Chugh, Vishal,Weyhermüller, Thomas,Werlé, Christophe
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p. 7176 - 7185
(2021/06/30)
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- Selective electrochemical oxidation of aromatic hydrocarbons and preparation of mono/multi-carbonyl compounds
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A selective electrochemical oxidation was developed under mild condition. Various mono-carbonyl and multi-carbonyl compounds can be prepared from different aromatic hydrocarbons with moderate to excellent yield and selectivity by virtue of this electrochemical oxidation. The produced carbonyl compounds can be further transformed into α-ketoamides, homoallylic alcohols and oximes in a one-pot reaction. In particular, a series of α-ketoamides were prepared in a one-pot continuous electrolysis. Mechanistic studies showed that 2,2,2-trifluoroethan-1-ol (TFE) can interact with catalyst species and generate the corresponding hydrogen-bonding complex to enhance the electrochemical oxidation performance. [Figure not available: see fulltext.]
- Li, Zhibin,Zhang, Yan,Li, Kuiliang,Zhou, Zhenghong,Zha, Zhenggen,Wang, Zhiyong
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p. 2134 - 2141
(2021/09/29)
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- Erratum: Ruthenium-catalyzed C-H hydroxylation in aqueous acid enables selective functionalization of amine derivatives (Journal of the American Chemical Society (2017) 139:28 (9503-9506) DOI: 10.1021/jacs.7b05469)
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Page 9504. The structure of product 3cc in Table 2 was found to be mis-assigned. We thank Prof. Phil Baran and Dr. Rafael Navratil for bringing this error to our attention. The correct structure contains an additional benzylic alcohol at the C-9 position of the steroid (3cc′, shown below). With the accompanying change in molecular weight, the isolated yield is 29%. Supporting Information. The incorrect structure and yield also appeared on pages S20 and S84 in the SI. Given this, the HRMS entry on page S20 should read as follows: “HRMS (ESI-TOF) m/z calcd for C19H18F3O5S+ (M-O+Na)+ 415.0822, found 415.0857”. The complete corrected SI is provided here.
- Mack, James B.C.,Gipson, John D.,Du Bois,Sigman, Matthew S.
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supporting information
p. 3016 - 3016
(2021/03/01)
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- HCl-Catalyzed Aerobic Oxidation of Alkylarenes to Carbonyls
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The construction of C?O bonds through C?H bond functionalization remains fundamentally challenging. Here, a practical chlorine radical-mediated aerobic oxidation of alkylarenes to carbonyls was developed. This protocol employed commercially available HCl as a hydrogen atom transfer (HAT) reagent and air as a sustainable oxidant. In addition, this process exhibited excellent functional group tolerance and a broad substrate scope without the requirement for external metal and oxidants. The mechanistic hypothesis was supported by radical trapping, 18O labeling, and control experiments.
- Ding, Ling,Liu, Yuxiu,Niu, Kaikai,Shi, Xiaodi,Song, Hongjian,Wang, Qingmin
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- An efficient and practical aerobic oxidation of benzylic methylenes by recyclable: N -hydroxyimide
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An efficient and practical benzylic aerobic oxidation catalyzed by cheap and simple N-hydroxyimide organocatalyst has been achieved with high yields and broad substrate scope. The organocatalyst used can be recycled and reused by simple workup and only minute amount (1 mol% in most cases) of simple iron salt is used as promoter. Phenyl substrates with mild and strong electron-withdrawing group could also be oxygenated in high yields as well as other benzylic methylenes. Influence of substituents, gram-scale application, catalysts decay and general mechanism of this methodology has also been discussed. This journal is
- Wang, Jian,Zhang, Cheng,Ye, Xiao-Qing,Du, Wenting,Zeng, Shenxin,Xu, Jian-Hong,Yin, Hong
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p. 3003 - 3011
(2021/01/28)
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- Revisiting the synthesis of aryl nitriles: a pivotal role of CAN
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Facilitated by the dual role of Ceric Ammonium Nitrate (CAN), herein we report a cost-effective approach for the cyanation of aryl iodides/bromides with CAN-DMF as an addition to the existing pool of combined cyanation sources. In addition to being an oxidant, CAN acts as a source of nitrogen in our protocol. The reaction is catalyzed by a readily available Cu(ii) salt and the ability of CAN to generate ammonia in the reaction medium is utilized to eliminate the additional requirement of a nitrogen source, ligand, additive or toxic reagents. The mechanistic study suggests an evolution of CN?leading to the synthesis of a variety of aryl nitriles in moderate to good yields. The proposed mechanism is supported by a series of control reactions and labeling experiments.
- Saikia, Rakhee,Park, Kwihwan,Masuda, Hayato,Itoh, Miki,Yamada, Tsuyoshi,Sajiki, Hironao,Mahanta, Sanjeev P.,Thakur, Ashim J.
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p. 1344 - 1351
(2021/02/27)
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- Iron(II)-Catalyzed Biomimetic Aerobic Oxidation of Alcohols
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We report the first FeII-catalyzed biomimetic aerobic oxidation of alcohols. The principle of this oxidation, which involves several electron-transfer steps, is reminiscent of biological oxidation in the respiratory chain. The electron transfer from the alcohol to molecular oxygen occurs with the aid of three coupled catalytic redox systems, leading to a low-energy pathway. An iron transfer-hydrogenation complex was utilized as a substrate-selective dehydrogenation catalyst, along with an electron-rich quinone and an oxygen-activating Co(salen)-type complex as electron-transfer mediators. Various primary and secondary alcohols were oxidized in air to the corresponding aldehydes or ketones with this method in good to excellent yields.
- B?ckvall, Jan-E.,Guemundsson, Arnar,Schlipk?ter, Kim Elisabeth
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supporting information
p. 5403 - 5406
(2020/02/27)
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- Acyl radicals from α-keto acids using a carbonyl photocatalyst: Photoredox-catalyzed synthesis of ketones
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Acyl radicals have been generated from α-keto acids using inexpensive and commercially available 2-chloro-thioxanthen-9-one as the photoredox catalyst under visible light illumination. These reactive species added to olefins or coupled with aryl halides via a bipyridylstabilized Ni(II) catalyst, enabling easy access to a diverse range of ketones. This reliable, atom-economical, and eco-friendly protocol is compatible with a wide range of functional groups.
- Zhu, Da-Liang,Wu, Qi,Young, David James,Wang, Hao,Ren, Zhi-Gang,Li, Hong-Xi
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supporting information
p. 6832 - 6837
(2020/10/12)
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- Heterogeneous carbon nitride photocatalyst for C-C bond oxidative cleavage of vicinal diols in aerobic micellar medium
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A green and efficient visible-light promoted aerobic oxidative C-C bond cleavage of vicinal diols in micellar medium has been developed. This protocol used graphitic carbon nitride with nitrogen vacancies (CN620) as a metal-free recyclable photocatalyst and CTAB as surfactant in water. Control experiments and the ESR results indicated that superoxide radicals and valence band holes played an important role in the reaction. Further isotope experiments suggested both a β-scission/HAT pathway and an oxidation/hydrolysis/dehydration pathway for the reaction, which is different from previous reports. The semiconductor/micellar catalyst system can be recycled at least 10 times without a significant reduction in activity. Furthermore, this reaction could be carried out under solar light irradiation and was applicable to large-scale reactions with similar results.
- Chen, Jiayang,Chen, Shengjun,Dong, Xinyu,Hong, Mei,Ni, Bangqing,Niu, Tengfei,Zhang, Tianhao
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supporting information
p. 5042 - 5049
(2020/08/25)
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- A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
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We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
- Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
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p. 4617 - 4629
(2020/05/19)
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- Palladium-Catalyzed Cyanation of Aryl Halides Using Formamide and Cyanuric Chloride as a New “CN” Source
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A new source of “CN” employing formamide and cyanuric chloride is introduced for the cyanation reactions. The treatment of formamide and 2,4,6-trichloro-1,3,5-triazine (TCT; cyanuric chloride) afforded an efficient cyanating agent which it can be used as a nontoxic, readily available, and non-expensive reagent in the cyanation transformations. In this study, palladium-catalyzed cyanation of aryl halides was successfully accomplished using this new “CN” source in high yields.
- Niknam, Esmaeil,Panahi, Farhad,Khalafi-Nezhad, Ali
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p. 2699 - 2707
(2020/04/08)
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- Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds
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A metal-free approach for the oxidative cleavage of carbon–carbon double bonds of olefins to carbonyl compounds was established by using oxidant m-CPBA and non-metallic organocatalyst PhI in toluene/H2O. A broad scope of aromatic olefins was used. All the reactions proceeded smoothly at 35 °C in short reaction time to furnish the respective mono- and double carbonyl compounds selectively in moderate to good yields.
- Du, Lele,Wang, Zechao,Wu, Junliang
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supporting information
(2020/07/20)
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- Hydration of terminal alkynes catalyzed by cobalt corrole complex
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Cobalt(III) corrole was firstly applied to the hydration of terminal alkynes. The alkyne hydration proceeded in good to excellent yield with 0.03 to 0.3 mol% cobalt corrole catalyst loading. A wide range of substrates were tolerated. Particularly, the reaction can give 90% yield in a gram scale experiment.
- Lai, Jia-Wei,Liu, Zhao-Yang,Chen, Xiao-Yan,Zhang, Hao,Liu, Hai-Yang
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supporting information
(2020/10/02)
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- Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds
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Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is
- Fu, Hua,Liu, Can,Liu, Yong,Yang, Haijun,Zhu, Xianjin
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supporting information
p. 4357 - 4363
(2020/07/14)
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- A Free-Radical Reduction and Cyclization of Alkyl Halides Mediated by FeCl2
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Iron mediated catalytic reactions are of great interest in the field of organic synthesis because they are economic and naturally abundant. However, the use of iron catalyst in the field of free radical cyclization or reduction of alkyl halides remains limited. Here we describe the use of an unprecedented combination of iron and zinc in the reduction and 5-exo-trig radical cyclization of alkyl halides under mild condition in the absence of added ligands or additives. The method is distinguished by its wide scope, functional group tolerance and the use of 1,4-cyclohexadiene as the source of hydrogen, which aids easy purification.
- Pulikottil, Feba Thomas,Pilli, Ramadevi,Murugesan, Vetrivelan,Krishnan, Chandu G.,Rasappan, Ramesh
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p. 2438 - 2442
(2019/04/30)
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- Immobilized palladium nanoparticles on a cyclodextrin-polyurethane nanosponge (Pd-CD-PU-NS): An efficient catalyst for cyanation reaction in aqueous media
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Immobilized palladium nanoparticles on a cyclodextrin-polyurethane nanosponge (Pd-CD-PU-NS) were found to be an efficient heterogeneous catalyst in the cyanation reaction of aryl halides in aqueous media. This catalyst system is containing palladium nanoparticles with a size of ～7 nm. Moreover, the CD-PU-NS support formed microsphere-shaped structures with a size of ～100–200 nm. The TEM images show that Pd nanoparticles were formed in near spherical shape morphology and were immobilized in the structure of the CD-PU-NS support. Under our optimized reaction conditions, aryl cyanides were obtained in high yields in the presence of the Pd-CD-PU-NS catalyst. Our results demonstrated that the Pd-CD-PU-NS catalyst is highly effective in the cyanation reaction in aqueous media. Furthermore, the catalyst could be simply extracted from the reaction mixture, providing an efficient methodology for the synthesis of aryl cyanides. The Pd-CD-PU-NS catalyst could be recycled four times with almost consistent catalytic efficiency.
- Khajeh Dangolani, Soheila,Sharifat, Sara,Panahi, Farhad,Khalafi-Nezhad, Ali
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supporting information
p. 256 - 265
(2019/06/07)
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- Pd(II)-immobilized on a nanoporous triazine-based covalent imine framework for facile cyanation of haloarenes with K4Fe(CN)6
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A porous covalent organic framework incorporated with both imine and triazine functionalities (TPA-TCIF) was synthesized by Schiff-base condensation of 2,4,6-tris(4-aminophenyl)triazine and tris(4-formylphenyl)amine under the solvothermal condition of a 1-butanol:1,2-dichlorobenzene mixture. The resulting TPA-TCIF was a highly ordered crystalline network with surface area of 2938 m2 g?1, which was among the highest reported imine-based porous covalent organic frameworks. TPA-TCIF was also stable in water and other organic solvents. Pd(II) was immobilized into TPA-TCIF network and the resultant Pd/TPA-TCIF was tested as a catalyst for the additive-free cyanation of haloarenes with non-toxic K4[Fe(CN)6]. The catalyst showed excellent catalytic activity, and both electron-donating / -withdrawing groups attached to the para- and meta-positions of bromoarenes produced the respective nitriles with good to excellent yields. The catalyst could be reused up to five times without noticeable loss of activity or catalyst poisoning by cyanide ions during the reaction.
- Puthiaraj, Pillaiyar,Yu, Kwangsun,Shim, Sang Eun,Ahn, Wha-Seung
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- 3-BocNH-ABNO-catalyzed aerobic oxidation of alcohol at room temperature and atmospheric pressure
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A transition-metal-free catalytic system has been developed for selective transformation of alcohol to aldehydes or ketones. The reactions were performed with 3-(tert-butoxycarbonylamino)-9-azabicyclo[3.3.1]nonane N-oxyl (3-BocNH-ABNO) as the catalyst, NaNO2 as the co-catalyst, molecular oxygen as the terminal oxidant, and AcOH as the solvent under room temperature. This catalytic system exhibited broad functional group tolerance. A series of alcohol substrates, including primary and secondary benzylic alcohols, heteroaromatic analogues, primary and secondary aliphatic alcohols, could be converted into their corresponding aldehydes and ketones in good conversions and selectivities.
- Zhao, Yajing,Li, Yutong,Shen, Zhenlu,Hu, Xinquan,Hu, Baoxiang,Jin,Sun, Nan,Li, Meichao
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supporting information
(2019/08/06)
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- 1,10-Phenanthroline- or Electron-Promoted Cyanation of Aryl Iodides
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A 1,10-phenanthroline-promoted cyanation of aryl iodides has been developed. 1,10-Phenanthroline worked as an organocatalyst for the reaction of aryl iodides with tetraalkylammonium cyanide to afford aryl cyanides. A similar reaction occurred through an electroreductive process.
- Hirata, Takayuki,Mandai, Hiroki,Midorikawa, Koji,Mitsudo, Koichi,Suga, Seiji,Yoshioka, Kazuki
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supporting information
p. 1209 - 1214
(2019/06/08)
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- An Insight into Nitromethane as an Organic Nitrile Alternative Source towards the Synthesis of Aryl Nitriles
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Directed by an unusual in situ reduction of CuII, our protocol is a simple CuI-mediated synthesis of aryl nitriles, with inexpensive and readily available nitromethane as the cyanating source, in moderate to good yields. Exhibiting a wide substrate scope, the method involves simple reaction conditions, is additive free with low catalyst loading. The plausible mechanism of cyanation of aryl halides is elucidated by a congregation of three cycles, namely the in situ reduction of CuII species by nitromethane, generation of HCN species from nitromethane and a regular organometallic pathway which releases the nitrile derivative. The detail of the mechanism of generation of CN– from nitromethane is computationally validated. Our protocol holds the distinction of involving a rarely encountered CuI catalytic species as well as facile in situ generation of nucleophilic CN– to yield synthetically useful aromatic nitriles.
- Saikia, Rakhee,Dey Baruah, Satyajit,Deka, Ramesh C.,Thakur, Ashim J.,Bora, Utpal
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p. 6211 - 6216
(2019/11/05)
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- Retro-Corey-Chaykovsky Epoxidation: Converting Geminal Disubstituted Epoxides to Ketones
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Corey-Chaykovsky epoxidation has been widely applied in the conversion of aldehydes and ketones to epoxides with sulfonium and sulfoxonium ylides. The reverse transformation is realized for conversion of geminal disubstituted epoxides to ketones in the presence of DABCO in refluxing mesitylene. The method is a weak basic transformation from epoxides to ketones with loss of a methylene group and can be applied as an alternative strategy of the acid-catalyzed Meinwald rearrangement or oxidation for conversion of epoxides to carbonyl compounds.
- Li, Siqi,Li, Pingfan,Xu, Jiaxi
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- Selective Synthesis of Secondary and Tertiary Amines by Reductive N-Alkylation of Nitriles and N-Alkylation of Amines and Ammonium Formate Catalyzed by Ruthenium Complex
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A new ruthenium catalytic system for the syntheses of secondary and tertiary amines via reductive N-alkylation of nitriles and N-alkylation of primary amines is proposed. Isomeric complexes 8 catalyze transfer hydrogenation and N-alkylation of nitriles in ethanol to give secondary amines. Unsymmetrical secondary amines can be produced by N-alkylation of primary amines with alcohols via the borrowing hydrogen methodology. Aliphatic amines were obtained with excellent yields, while only moderate conversions were observed for anilines. Based on kinetic and mechanistic studies, it is suggested that the rate determining step is the hydrogenation of intermediate imine to amine. Finally, ammonium formate was applied as the amination reagent for alcohols in the presence of ruthenium catalyst 8. Secondary amines were obtained from primary alcohols within 24 hours at 100 °C, and tertiary amines can be produced after prolonged heating. Secondary alcohols can only be converted to secondary amines with moderate yield. Based on mechanistic studies, the process is suggested to proceed through an ammonium alkoxy carbonate intermediate, where carbonate acts as an efficient leaving group.
- Alshakova, Iryna D.,Nikonov, Georgii I.
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p. 5370 - 5378
(2019/06/14)
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- Nucleophilic Organic Base DABCO-Mediated Chemospecific Meinwald Rearrangement of Terminal Epoxides into Methyl Ketones
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Nucleophilic organic base DABCO (1,4-diazabicyclo[2.2.2]octane)-mediated Meinwald rearrangement of various epoxides was investigated. 2-Aryl-, alkenyl-, and alkynylepoxides generate the corresponding methyl ketones chemospecifically in good to excellent yields. The current DABCO-mediated Meinwald rearrangement of epoxides features readily accessible starting materials, a wide substrate scope, a transition-metal- and acid-free environment, and chemospecificity in the isomerization of epoxides.
- Li, Siqi,Shi, Yi,Li, Pingfan,Xu, Jiaxi
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p. 4443 - 4450
(2019/04/30)
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- Preparing method of aromatic nitrile or alkenyl nitrile compound
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The invention discloses a preparing method of an aromatic nitrile or alkenyl nitrile compound. The preparing method comprises the following step that under protection of inert gas, an aryl or heteroaryl sulphonate compound shown in a formula II or an alkenyl sulphonate compound shown in a formula IV and a cyanation reagent are subjected to a cross-coupling reaction as is shown below in a solvent under the condition of the presence of a nickel complex, metal zinc and an additive to obtain the aromatic nitrile or alkenyl nitrile compound, wherein 4-dimethylamiopryidine (DMAP) is adopted as the additive, and zinc cyanide is adopted as the cyanation reagent. By means of the preparing method, cyanation of aryl sulphonate, heteroaryl sulphonate or alkenyl sulphonate can be simply and efficientlyachieved with a cheap catalysis system; moreover, the functional group compatibility and substrate universality are good, and a better application prospect and higher using value are provided for achieving industrial synthesis of the aromatic nitrile or alkenyl nitrile compound.
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Paragraph 0130-0132; 0232-0267
(2019/10/01)
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- Sulfuryl Fluoride Mediated Conversion of Aldehydes to Nitriles
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Aliphatic, aromatic, and heteroaromatic aldehydes were readily converted to corresponding nitriles in a one-pot reaction sequence with hydroxylamine and sulfuryl fluoride. The reaction proceeds at room temperature, does not require metal catalysts and special precautions, and produces nitriles in excellent yields. It is compatible with a variety of functional groups, can be performed in aqueous and organic solvents, and is readily scalable to multigram quantities. Mild conditions and high selectivity of the reaction enabled the construction of polyfunctional probes containing nitrile, alkyne, azide, and fluorosulfate groups for further orthogonal derivatization.
- Gurjar, Jitendra,Bater, Jorick,Fokin, Valery V.
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supporting information
p. 1906 - 1909
(2019/01/24)
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- Visible light-induced direct conversion of aldehydes into nitriles in aqueous medium using Co@g-C3N4 as photocatalyst
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Unprecedented Co@g-C3N4 catalyzed visible light driven efficient conversion of a variety of aldehydes into corresponding nitriles is reported. Operational simplicity, excellent yield of pure products (87–94%), ambient reaction condition, using aqueous methanol as solvent, visible-light photocatalysis are the salient features of envisaged methodology for direct conversion of aldehydes into nitriles. Furthermore, reusability of Co@g-C3N4 was checked up to five runs and it was noticed that there was no substantial change in morphology as well as the catalytic efficiency of catalyst.
- Verma, Fooleswar,Shukla, Prashant,Bhardiya, Smita R.,Singh, Manorama,Rai, Ankita,Rai, Vijai K.
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- Electrochemical benzylic oxidation of C-H bonds
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Oxidized products have become increasingly valuable as building blocks for a wide variety of different processes and fine chemistry, especially in the benzylic position. We report herein a sustainable protocol for this transformation through C-H functionalization and is performed using electrochemistry as the main power source and tert-butyl hydroperoxide as the radical source for the C-H abstraction. The temperature conditions reported here do not increase above 50 °C and use an aqueous-based medium. A broad substrate scope is explored, along with bioactive molecules, to give comparable and increased product yields when compared to prior reported literature without the use of electrochemistry.
- Marko, Jason A.,Durgham, Anthony,Bretz, Stacey Lowery,Liu, Wei
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supporting information
p. 937 - 940
(2019/01/23)
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- Sonochemical Preparation of Dipicolinamide Mn-complexes and Their Application as Catalysts Towards Sono-synthesis of Ketones
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A series of non-heme Mn-complexes has been synthesized by the sonication of manganese (II)chloride and bis-amides (condensation products of 2-picolinic acid and o-phenylenediamines). The Mn-complexes effectively promote the oxidation of unactivated aliphatic and benzylic C─H and N-bearing heterocycles substrates with low catalyst loading using eco-friendly hydrogen peroxide in the presence of acetic acid as additive under ultrasonic irradiation. Chromatographic studies revealed that the corresponding ketones are the only detectable products. Noteworthy, the presence of electron donors in the catalyst structure significantly increased the reaction yields. The substantial lowering of the oxidation reaction yields by adding ionol (2,6-di-tert-butyl-4-methylphenol) as a free radical trap suggesting a free radical reaction pathway.
- Arafa, Wael A. A.
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p. 1403 - 1412
(2019/02/25)
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- 2-Amino-4-arylthiazoles through One-Pot Transformation of Alkylarenes with NBS and Thioureas
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Treatment of alkylarenes with N-bromosuccinimide in a mixture of ethyl acetate and water at 60 °C, a mixture of acetonitrile and water at 80 °C, or a mixture of diethyl carbonate and water under irradiation with a tungsten lamp, followed by a reaction with thioureas or arenethioamides provided the corresponding 2-amino- 4-arylthiazoles or 2,4-diarylthiazoles in good to moderate yields, respectively, in one pot. The present reaction is an efficient one-pot transformation method of alkylarenes into 2-amino-4-arylthiazoles and 2,4-diarylthiazoles directly under mild and transition-metal-free conditions.
- Shibasaki, Kaho,Togo, Hideo
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p. 2520 - 2527
(2019/04/04)
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- Preparation method of aromatic nitrile compound or heteroaromatic nitrile compound
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The invention discloses a preparation method of an aromatic nitrile compound or a heteroaromatic nitrile compound. The preparation method comprises: under the protection of an inert gas, in a solvent,under the actions of a nickel catalyst, a ligand, metal zinc and an additive, carrying out a reaction on a cyanation reagent and halogenated aromatic hydrocarbon or halogenated heteroaromatic hydrocarbon. According to the present invention, by using the inexpensive and easily-available nickel catalyst and the ligand, the halogenated aromatic hydrocarbon or halogenated heteroaromatic hydrocarbon,especially the chlorinated aromatic hydrocarbon or chlorinated heteroaromatic hydrocarbon with characteristics of low price, easy obtaining and low reaction activity can mildly and efficiently react with the cyanation reagent with low toxicity to prepare the aromatic nitrile compound or heteroaromatic nitrile compound; and the preparation method has advantages of simple operation, mildness, high efficiency and the like, and further has characteristics of good functional group compatibility, good universality of substrate and the like.
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Paragraph 0043; 0045; 0127-0129
(2018/11/03)
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- Immobilization of an Aminobisphosphine–PdII Complex over Graphene Oxide: An Efficient and Reusable Catalyst for Suzuki–Miyaura, Ullmann Coupling and Cyanation Reactions
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The grafting of an aminobis(phosphine)–PdII complex (PNP–PdII) [PdCl2{(Ph2P)2N(CH2)3Si(OMe)3}] (2) on graphene oxide (GO) has been carried out by a condensation reaction between methoxysilane groups of 2 and hydroxyl groups of GO. The composite material was characterized by FTIR spectroscopy, solid-state 31P NMR spectroscopy, SEM, TEM, XPS and ICP-AES techniques. All these tools support the clean immobilization of compound 2 on GO. The composite material showed high catalytic activity in Suzuki–Miyaura, Ullmann coupling and cyanation reactions. The heterogeneity of the composite was confirmed by a hot filtration test. The immobilized PNP–PdII shows comparable activity to its homogeneous analogue 2. The recycling ability of the catalyst was examined for five consecutive runs, which showed little or no reduction in its catalytic efficiency.
- Sengupta, Debasish,Pandey, Madhusudan K.,Mondal, Dipanjan,Radhakrishna, Latchupatula,Balakrishna, Maravanji S.
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p. 3374 - 3383
(2018/05/08)
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- Green Synthesis of Palladium Nanoparticles: Applications in Aryl Halide Cyanation and Hiyama Cross-Coupling Reaction Under Ligand Free Conditions
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Abstract: In the current work, palladium nanoparticles (Pd NPs) were prepared from palladium acetate biogenically using the aqueous-ethanolic extract of black pepper (Piper nigrum) and characterized by various analytical techniques like XRD, FE-SEM, EDS, TEM, ATR-IR, UV–Vis spectroscopy, BET, TGA and ICP-OES analysis. The reduction of Pd(II)?to?Pd(0) is achieved by the action of various phytochemicals present in the black pepper extract like phenols, acids, pellitorine, ethyl piperonyl cyanoacetate, piperine and N-isobutyl-tetradeca-2,4-dienamide. The biosynthesized Pd NPs shown excellent catalytic activity in aryl halide cyanation and Hiyama cross-coupling reactions. Also, less toxic potassium hexacyanoferrate(II) trihydrate was used as cyanide source in aryl halide cyanation and Hiyama cross-coupling was performed under fluoride free condition. Both reactions proceeded well with Pd NPs under ligand free circumstances to give good to excellent yields. The Pd NPs were recovered after each reaction and recycled up to five times in aryl halide cyanation and ten times in Hiyama cross-coupling without considerable loss in the activity. Graphical Abstract: Green synthesis of palladium nanoparticles: applications in aryl halide cyanation and Hiyama cross-coupling reaction under ligand free conditions. [Figure not available: see fulltext.].
- Kandathil, Vishal,Dateer, Ramesh B.,Sasidhar,Patil, Shivaputra A.,Patil, Siddappa A.
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p. 1562 - 1578
(2018/04/02)
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- A Porous Organic Poly(triphenylimidazole) Decorated with Palladium Nanoparticles for the Cyanation of Aryl Iodides
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A new porous organic poly(triphenylimidazole), PTPI-Me, was prepared through a Yamamoto self-coupling reaction of 2,4,5-tris-(4-bromophenyl)-1-methyl-1H-imidazole (TPI-Me) in the presence of bis(1,5-cyclooctadiene)nickel(0). The polymer was subsequently decorated with Pd nanoparticles (NPs) to afford a heterogeneous cyanation catalyst, Pd@PTPI-Me. Pd NPs with an average diameter of 2.7 nm were grown within the PTPI-Me framework, owing to the coordination of the imidazole rings to the Pd species. The resultant Pd@PTPI-Me catalyst, with a Pd loading of 0.13 mmol g?1, exhibited superior catalytic activity for the cyanation of aryl iodides. More importantly, the heterogeneous catalyst was also readily recycled and displayed negligible deactivation after five cycles.
- Yu, Haiwen,Xu, Siqi,Liu, Yijiang,Chen, Hongbiao,Li, Huaming
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p. 2708 - 2713
(2018/09/06)
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- HKUST-1/ABNO-catalyzed aerobic oxidation of secondary benzyl alcohols at room temperature
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Efficient heterogeneous Cu-catalyzed aerobic oxidation of benzyl alcohols was discolsed. The combination of HKUST-1 and ABNO exhibited enhanced catalytic activity compare to the previous HKUST-1/TEMPO system in aerobic oxidation of benzyl alcohols. It was observed that the present catalyst was intrinsically heterogeneous and reusable.
- Kim, Myeong Jin,Jung, Yoo Eil,Lee, Chang Yeon,Kim, Jinho
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supporting information
p. 2722 - 2725
(2018/06/20)
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- Nickel-Catalyzed Cyanation of Phenol Derivatives with Zn(CN)2 Involving C-O Bond Cleavage
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An efficient nickel-catalyzed cyanation of aryl sulfonates, fluorosulfonates, and sulfamates with Zn(CN)2 was developed, which provides a facile access to the nitrile products in generally good to excellent yields. The reaction is accomplished by using NiII complex as the precatalyst and DMAP as the additive. The method also displays wide functional group compatibility; for example, keto, methoxy, N,N-dimethylamino, cyano, ester, and pyridyl groups are well-tolerated during the reaction process.
- Gan, Yi,Wang, Gaonan,Xie, Xin,Liu, Yuanhong
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p. 14036 - 14048
(2018/11/03)
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- Thiyl radical promoted chemo- and regioselective oxidation of CC bonds using molecular oxygen: Via iron catalysis
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The first example of the thiyl radical promoted ligand-free iron-catalyzed oxidative cleavage of alkenes using molecular oxygen (1 atm) has been developed. The reaction proceeds under mild reaction conditions with high efficiency and high chemo- and regioselectivity. It features a broad substrate scope and excellent functional group compatibility, enabling facile access to valuable molecules for application in medicinal chemistry. Preliminary mechanistic studies reveal that a vital intermediate dioxetane might be involved in the reaction and a thiyl radical plays a synergistic role in facilitating the selective oxidation of the CC bond.
- Xiong, Baojian,Zeng, Xiaoqin,Geng, Shasha,Chen, Shuo,He, Yun,Feng, Zhang
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supporting information
p. 4521 - 4527
(2018/10/17)
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- Oxidation of Tertiary Aromatic Alcohols to Ketones in Water
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A new rosin-based amphiphile enables the oxidation of tertiary aromatic alcohols in water under mild conditions. The oxidation process is mediated by β-scission of alkoxy radicals. Our catalyst system including the surfactant, catalysts, and water can be easily recycled within the same reaction vial. (Figure presented.).
- Chen, Dengfeng,Zhang, Yuchen,Pan, Xingyu,Wang, Fei,Huang, Shenlin
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supporting information
p. 3607 - 3612
(2018/09/18)
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