- Copper and N-Heterocyclic Carbene-Catalyzed Oxidative Amidation of Aldehydes with Amines
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A one-pot two-step oxidative process has been developed for the tert-butyl hydroperoxide mediated transformation of aldehydes and amines into amides catalyzed by copper(I) iodide and an N-heterocyclic carbene. The process is additive-free and does not require the amine to be transformed into its hydrochloride salts. The method is simple and practicable, has a broad substrate scope, and uses economical, feasible, and abundant reagents.
- Singh, Ashmita,Narula, Anudeep Kumar
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supporting information
p. 718 - 722
(2021/02/26)
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- Direct Synthesis of Enamides via Electrophilic Activation of Amides
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A novel, one-step N-dehydrogenation of amides to enamides is reported. This reaction employs the unlikely combination of LiHMDS and triflic anhydride, which serves as both the electrophilic activator and the oxidant, and is characterized by its simple setup and broad substrate scope. The synthetic utility of the formed enamides was readily demonstrated in a range of downstream transformations.
- Berger, Martin,Kaiser, Daniel,Maulide, Nuno,Spie?, Philipp
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supporting information
p. 10524 - 10529
(2021/07/28)
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- Photocatalytic aldehydes/alcohols/toluenes oxidative amidation over bifunctional Pd/MOFs: Effect of Fe-O clusters and Lewis acid sites
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Heterogeneous photocatalytic organic synthesis is fascinating because of the utilization of ubiquitous solar light for chemical transformations. Here, three Fe-MOFs with different Fe-O clusters, Lewis acid sites and morphologies were synthesized through coordination structure engineering. Pd/Fe-MOFs nanocomposites were used to challenge the amide bond green synthesis with visible light. Pd/MIL-101(Fe) exhibited the best photocatalytic performance due to the easily excited Fe3-μ3-oxo clusters for light absorption, the efficient photogenerated carriers separation and migration, the large amount of Lewis acid sites based aldehydes and amines condensation promotion and the efficient O2 reduction to superoxide radicals over photogenerated electron-rich Pd NPs. Various aldehydes, alcohols and toluenes could be transformed to amide compounds with amines over Pd/MIL-101(Fe) with just oxygen or air as the green oxidant and water as the by-product. One-pot C–C cross-coupling and photo-redox C–N coupling cascade reactions could also be achieved over Pd/MIL-101(Fe). This work shed light on the efficient and sustainable amide bonds synthesis.
- Bian, Fengxia,Cheng, Hongmei,Jiang, Heyan,Sun, Bin,Tan, Jiangwei,Zang, Cuicui
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p. 279 - 287
(2021/08/21)
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- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
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A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Pandey, Pragati,Bera, Jitendra K.
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supporting information
p. 9204 - 9207
(2021/09/20)
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- Catalytic N-Acylation of Cyclic Amines by Arylglyoxylic Acids via Radical-Radical Cross-Coupling
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A methodical mechanistic investigation allowed for the catalytic N-acylation of secondary cyclic amine counterparts by arylglyoxylic acids through radical-radical coupling. The reaction proceeds via a twofold SET-promoted Cu(I)/Cu(II) catalytic cycle under mild conditions. An analogous reaction variant allows for the N-acylation in a one-pot fashion directly starting from a secondary cyclic amine even in the presence of a second amine or hydroxy group.
- Bhadra, Sukalyan,Gupta, Aniket,Kumar Singh, Anupam,Rahaman, Ajijur
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p. 2198 - 2202
(2021/07/22)
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- Amidation of Aldehydes with Amines under Mild Conditions Using Metal-Organic Framework Derived NiO@Ni Mott-Schottky Catalyst
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Here we report a facile method for the synthesis of nickel oxide-nickel (NiO@Ni) Mott-Schottky catalyst employing metal-organic framework (MOF) as the precursor. A direct amidation protocol of aldehydes with amines has been optimized under mild conditions using NiO@Ni Mott-Schottky catalyst and it shows far better catalytic activity than the NiO?Ni nanoparticles prepared from simple Ni2+ salt under similar reaction conditions. The heterogeneous catalyst is robust, recyclable and efficient to provide comparable yield to costly ligand-based homogeneous Ni catalysts. The scope of the reaction protocol has been explored with variably substituted substrates. The reaction initiates by homolytic cleavage of peroxide and proceeds through radical mechanism.
- Goel, Bharat,Vyas, Ved,Tripathi, Nancy,Kumar Singh, Ajit,Menezes, Prashanth W.,Indra, Arindam,Jain, Shreyans K.
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p. 5743 - 5749
(2020/09/09)
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- Electrochemical Amide Bond Formation from Benzaldehydes and Amines: Oxidation by Cathodic-Generated Hydrogen Peroxide
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Although amide bond formation from aldehydes and amines is a popular synthetic tool, most of the previously reported reactions depend on transition-metal catalysts or expensive oxidants. We considered that a more environmentally benign and safer approach could be achieved by electrochemistry. Nineteen benzamide derivatives were obtained with this reaction. NMR studies, cyclic voltammetry (CV) investigations, and control experiments showed that the corresponding intermediate, a hemiaminal, was transformed into the amide by oxidation with hydrogen peroxide generated in situ by cathodic reduction of molecular oxygen.
- Kurose, Yuma,Imada, Yasushi,Okada, Yohei,Chiba, Kazuhiro
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supporting information
p. 3844 - 3846
(2020/06/23)
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- Organophotoredox-Mediated Amide Synthesis by Coupling Alcohol and Amine through Aerobic Oxidation of Alcohol
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The combination of an organic photocatalyst [4CzIPN (1,2,3,5-tetrakis(carbazol-9-yl)-4,6 dicyanobenzene) or 5MeOCzBN (2,3,4,5,6-pentakis(3,6-dimethoxy-9 H-carbazol-9-yl)benzonitrile)], quinuclidine, and tetra-n-butylammonium phosphate (hydrogen-bonding catalyst) was employed for amide bond formations. The hydrogen-bonded OH group activated the adjacent C?H bond of alcohols towards hydrogen atom transfer (HAT) by a radical species. The quinuclidinium radical cation, generated through single-electron oxidation of quinuclidine by the photocatalyst, employed to abstract a hydrogen atom from the α-C?H bond of alcohols selectively due to a polarity effect-produced α-hydroxyalkyl radical, which subsequently converted to the corresponding aldehyde under aerobic conditions. Then the coupling of the aldehyde and an amine formed a hemiaminal intermediate that upon photocatalytic oxidation produced the amide.
- Samanta, Samya,Shah, Sk. Sheriff,Shee, Maniklal,Singh, Amit Kumar,Singh, N. D. Pradeep,Venkatesh, Yarra
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supporting information
(2020/03/05)
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- Cobalt-catalyzed aminocarbonylation of (hetero)aryl halides promoted by visible light
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The catalytic aminocarbonylation of (hetero)aryl halides is widely applied in the synthesis of amides but relies heavily on the use of precious metal catalysis. Herein, we report an aminocarbonylation of (hetero)aryl halides using a simple cobalt catalyst under visible light irradiation. The reaction extends to the use of (hetero)aryl chlorides and is successful with a broad range of amine nucleophiles. Mechanistic investigations are consistent with a reaction proceeding via intermolecular charge transfer involving a donor-acceptor complex of the substrate and cobaltate catalyst.
- Alexanian, Erik J.,Veatch, Alexander M.
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p. 7210 - 7213
(2020/07/23)
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- Palladium-Catalyzed Desulfurative Amide Formation from Thioureas and Arylboronic Acids
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The development of the reactivity on carbene complexes would lead to the creation of novel synthetic strategies. We discovered herein the Pd-catalyzed desulfurative amide formation involved Suzuki-Miyaura coupling reaction, notably the Pd complex was generated in situ from thioureas, Ag salt and Pd catalyst. Silver salt was essential for the construction of this type of carbenes from available and stable thioureas and well participated in the catalytic cycle. We report a method for the synthesis of arylamides from arylboronic acids, which greatly enriched the application of thiourea chemistry and expanded the application of the Suzuki-Miyaura coupling.
- Su, Jianke,Li, Wendong,Li, Xin,Xu, Jian,Song, Qiuling
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p. 5664 - 5668
(2020/10/02)
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- Quinolin-8-yl Formate: A New Option for Small-Scale Carbonylation Reactions in Microwave Reactors
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A convenient procedure for conducting small-scale carbonylations of aryl or benzyl halides in a microwave reactor by using quinolin-8-yl formate is described. The resulting 8-acyloxyquinolines were shown to be more reactive than phenyl esters in acyl-tran
- Maddocks, Christopher J.,Aathimanikandan, Sivakumar V.,Richardson, Jeffery,Ruble, J. Craig
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p. 1608 - 1612
(2020/09/09)
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- IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
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An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
- Talukdar, Ranadeep
-
supporting information
p. 5303 - 5308
(2020/04/17)
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- Catalyst-Free, Metal-Free, and Chemoselective Transamidation of Activated Secondary Amides
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A simple protocol, which is catalyst-free, metal-free, and chemoselective, for transamidation of activated secondary amides in ethanol as solvent under mild conditions is reported. A wide range of amines, amino acids, amino alcohols, and the substituents, which are problematic in catalyzed transamidation, are tolerated in this methodology. The transamidation reaction was successfully extended to water as the medium as well. The present methodology appears to be better than the other catalyzed transamidations reported recently.
- Ramkumar, Rajagopal,Chandrasekaran, Srinivasan
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p. 921 - 932
(2019/02/10)
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- Frustrated Lewis Pair Catalyzed Hydrogenation of Amides: Halides as Active Lewis Base in the Metal-Free Hydrogen Activation
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A method for the metal-free reduction of carboxylic amides using oxalyl chloride as an activating agent and hydrogen as the final reductant is introduced. The reaction proceeds via the hydrogen splitting by B(2,6-F2-C6H3)3 in combination with chloride as the Lewis base. Density functional theory calculations support the unprecedented role of halides as active Lewis base components in the frustrated Lewis pair mediated hydrogen activation. The reaction displays broad substrate scope for tertiary benzoic acid amides and α-branched carboxamides.
- Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
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supporting information
p. 159 - 162
(2019/01/04)
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- Cross-Dehydrogenating Coupling of Aldehydes with Amines/R-OTBS Ethers by Visible-Light Photoredox Catalysis: Synthesis of Amides, Esters, and Ureas
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A straightforward synthesis of amides, ureas, and esters is reported by visible-light cross-dehydrogenating coupling (CDC) of aldehydes (or amine carbaldehydes) and amines/R-OTBS ethers by photoredox catalysis. The reaction is found to be general and high yielding. A plausible mechanistic pathway has been proposed for these transformations and is supported by appropriate controlled experiments.
- Pandey, Ganesh,Koley, Suvajit,Talukdar, Ranadeep,Sahani, Pramod Kumar
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supporting information
p. 5861 - 5865
(2018/09/21)
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- 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane: An efficient and high oxygen content oxidant in various oxidative reactions
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Several oxidative approaches namely thiocyanation of aromatic compounds, epoxidation of alkenes, amidation of aromatic aldehydes, epoxidation of α β-unsaturated ketones, oxidation of sulfides to sulfoxides and sulfones, bayer-villeger reaction, bromination and iodation of aniline and phenol derivatives oxidative esterification, oxidation of pyridines and oxidation of secondary, allylic and benzyllic alcohols were carried out using 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane as the potential solid oxidant which can be stored for several months without any loss in its activity. All of the procedures were accomplished via mild reaction conditions and the products were afforded in high yields and short reaction times.
- Khosravi, Kaveh,Naserifar, Shirin
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supporting information
p. 6584 - 6592
(2018/10/05)
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- Exploring organic photosensitizers based on hemicyanine derivatives: a sustainable approach for preparation of amide linkages
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Hemicyanine derivatives C1-C4 have been synthesized and show strong absorption in the visible region, good water solubility, efficient intersystem crossing, a high singlet oxygen quantum yield and high ability to transport electrons from the donor to acceptor. These hemicyanine derivatives were utilized as photocatalysts in additive/base free oxidative amidation of aromatic aldehydes in mixed aqueous media under visible light irradiation at low catalytic loading. The hemicyanine derivative C4 exhibited recyclability upto four cycles and reusability upto five cycles in oxidative amidation of aromatic aldehydes. Among all the hemicyanine derivatives, C4 shows a high photocatalytic efficiency due to a high singlet oxygen quantum yield. All the mechanism investigations showed involvement of reactive oxygen species generated by the organic triplet photosensitizer based on hemicyanine derivative for carrying out oxidative amidation of aldehyde. Our results will encourage the design of new “metal free” organic photosensitizers and their application in photocatalysis.
- Deol, Harnimarta,Kumar, Manoj,Bhalla, Vandana
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p. 31237 - 31245
(2018/09/13)
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- Straightforward α-Amino Nitrile Synthesis Through Mo(CO)6-Catalyzed Reductive Functionalization of Carboxamides
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The selective reduction of amides into an intermediate hemiaminal catalyzed by Mo(CO)6 together with the inexpensive and easy to handle TMDS (1,1,3,3-tetramethyldisiloxane) as reducing agent, followed by subsequent trapping of the hemiaminal with a cyanide source, allows for the straightforward synthesis of α-amino nitriles. The methodology presented here, displays high levels of chemoselectivity allowing for the reduction of amides in the presence of functional groups such as ketones, imines, aldehydes, and acids, which affords a simple route for the synthesis of α-amino nitriles with a broad scope of functionalities in high yields. Furthermore, the applicability of this methodology is demonstrated by scale up experiments and by derivatization of the target compounds into synthetically interesting products. The selective cyanation is successfully applied in late stage functionalizations of amide containing drugs and prolinol derivatives.
- Trillo, Paz,Slagbrand, Tove,Adolfsson, Hans
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p. 12347 - 12351
(2018/09/10)
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- Chemoselective amide reductions by heteroleptic fluoroaryl boron Lewis acids
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The heteroleptic borane catalyst (C6F5)2B(CH2CH2CH2)BPin is found to hydrosilylatively reduce amides under mild conditions. Simple tertiary amides can be reduced using Me2EtSiH, whereas tertiary benzamides required a more reactive secondary silane, Et2SiH2, for efficient reduction. The catalytic system described exhibits exceptional chemoselectivity in the reduction of oligoamides and tolerates functionalities which are prone to reduction under similar conditions.
- Peruzzi, Michael T.,Mei, Qiong Qiong,Lee, Stephen J.,Gagné, Michel R.
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supporting information
p. 5855 - 5858
(2018/06/13)
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- Integration of co2 reduction with subsequent carbonylation: Towards extending chemical utilization of co2
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Currently, it still remains a challenge to amplify the spectrum of chemical fixation of CO2, although enormous progress has been achieved in this field. In view of the widespread applications of CO in a myriad of industrial carbonylation processes, an alternative strategy is proposed in which CO2 reduction to CO is combined with carbonylation with CO generated ex situ, which affords efficiently pharmaceutically and agrochemically attractive molecules. As such, CO2 in this study was efficiently reduced by triphenysilane using CsF to CO in a sealed two-chamber reactor. Subsequently, palladium-catalyzed aminocar-bonylation, carbonylative Sonogashira coupling of aryl iodides, and rhodium(I)-mediated Pauson–Khand-type reaction proceeded smoothly to yield amides, alkynones, and bicyclic cy-clopentenones, respectively. Furthermore, the formed alkynones can further be successfully converted to a series of heterocycles, for example, pyrazoles, 3a-hydroxyisoxazolo[3,2-a]isoindol-8-(3aH)-one derivatives and pyrimidines in moderate yields. The striking features of this protocol include operational simplicity, high efficiency, and relatively broad application scope, which represents an alternative avenue for CO2 transformation.
- Lang, Xian-Dong,He, Liang-Nian
-
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- Mo(CO)6 as a Solid CO Source in the Synthesis of Aryl/Heteroaryl Weinreb Amides under Microwave-Enhanced Condition
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The facile transformation of aryl/heteroaryl nonaflates into corresponding amides via Pd-catalyzed aminocarbonylation using Mo(CO)6 as a solid CO source under microwave-enhanced condition is reported. The method was found to be tolerant with respect to a
- Ningegowda, Raghu,Bhaskaran, Savitha,Sajith, Ayyiliath M.,Aswathanarayanappa, Chandrashekar,Padusha, M. Syed Ali,Priya, Babu Shubha
-
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- Room Temperature Carbonylation of (Hetero) Aryl Pentafluorobenzenesulfonates and Triflates using Palladium-Cobalt Bimetallic Catalyst: Dual Role of Cobalt Carbonyl
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An efficient method for the carbonylation of (hetero) aryl pentafluorobenzenesulfonates and triflates under exceptionally mild conditions using palladium/dicobalt octacarbonyl [Pd/Co2(CO)8] has been developed. Besides acting as carbon monoxide (CO) source, Co2(CO)8enhances the reaction rate by accelerating the CO insertion through an in situ generated bimetallic palladium cobalt tetracarbonyl [Pd-Co(CO)4] complex. Under the optimized reaction condition, carbonylation of a wide range of activated and deactivated, as well as sterically hindered and heteroaromatic, substrates proceeded efficiently at room temperature. The high chemoselectivity and improved synthesis of biologically relevant Isoguvacine and Lazabemide intermediates highlights its scope as a valuable synthetic method. The generality of this protocol was further extended to other electrophiles (bromides, chlorides and tosylates). (Figure presented.).
- Joseph, Jayan T.,Sajith, Ayyiliath M.,Ningegowda, Revanna C.,Shashikanth, Sheena
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supporting information
p. 419 - 425
(2017/02/10)
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- Palladium-Catalyzed Oxidative Carbonylation of Aryl Hydrazines with CO and O2 at Atmospheric Pressure
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Palladium-catalyzed aerobic oxidative aminocarbonylation and alkoxycarbonylation reactions with aryl hydrazines as coupling partners have been developed. The oxidative carbonylation of aryl hydrazines proceeded smoothly at atmospheric pressure CO, employi
- Tu, Yongliang,Yuan, Lin,Wang, Tao,Wang, Changliu,Ke, Jiamei,Zhao, Junfeng
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p. 4970 - 4976
(2017/05/12)
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- Copper-Catalyzed Carbonylative Cross-Coupling of Arylboronic Acids with N-Chloroamines for the Synthesis of Aryl Amides
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A novel copper-catalyzed carbonylative cross-coupling between N-chloroamines and arylboronics acids has been developed. With copper(I) oxide as the catalyst, various desired amide compounds were produced in moderate to good yields. Functional groups such as iodide and alkene are tolerated. Notably, this is the first example of a copper-catalyzed aminocarbonylation with N-chloroamines.
- Yin, Zhiping,Wang, Zechao,Li, Wanfang,Wu, Xiao-Feng
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p. 1769 - 1772
(2017/04/13)
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- CuCl/TBHP catalyzed synthesis of amides from aldehydes and amines in water
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A CuCl/TBHP catalyzed amidation of aldehydes with amine under aqueous media is described. Both aliphatic and aromatic aldehydes coupled with a variety of amines under the reaction conditions employed.
- Lu, Shao-Yi,Badsara, Satpal Singh,Wu, Yi-Chun,Reddy, Daggula Mallikarjuna,Lee, Chin-Fa
-
supporting information
p. 633 - 636
(2016/01/26)
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- Chelating Bis(1,2,3-triazol-5-ylidene) Rhodium Complexes: Versatile Catalysts for Hydrosilylation Reactions
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NHC-rhodium complexes (NHC=N-heterocyclic carbenes) have been widely used as efficient catalysts for hydrosilylation reactions. However, the substrates were mostly limited to reactive carbonyl compounds (aldehydes and ketones) or carbon-carbon multiple bonds. Here, we describe the application of newly-developed chelating bis(tzNHC)-rhodium complexes (tz=1,2,3-triazol-5-ylidene) for several reductive transformations. With these catalysts, the formal reductive methylation of amines using carbon dioxide, the hydrosilylation of amides and carboxylic acids, and the reductive alkylation of amines using carboxylic acids have been achieved under mild reaction conditions.
- Nguyen, Thanh V. Q.,Yoo, Woo-Jin,Kobayashi, Shu
-
supporting information
p. 452 - 458
(2016/02/12)
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- Covalent triazine framework-supported palladium as a ligand-free catalyst for the selective double carbonylation of aryl iodides under ambient pressure of CO
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Carbonylation of aryl iodides with amines under atmospheric pressure of CO, catalyzed by Pd/CTFs (covalent triazine frameworks) without any specific additives, leads to the highly selective synthesis of α-ketoamides.
- Wang, Zhifang,Liu, Cuibo,Huang, Yi,Hu, Yuchen,Zhang, Bin
-
supporting information
p. 2960 - 2963
(2016/02/19)
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- Practical Synthesis of Amides via Copper/ABNO-Catalyzed Aerobic Oxidative Coupling of Alcohols and Amines
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A modular Cu/ABNO catalyst system has been identified that enables efficient aerobic oxidative coupling of alcohols and amines to amides. All four permutations of benzylic/aliphatic alcohols and primary/secondary amines are viable in this reaction, enabling broad access to secondary and tertiary amides. The reactions exhibit excellent functional group compatibility and are complete within 30 min-3 h at rt. All components of the catalyst system are commercially available.
- Zultanski, Susan L.,Zhao, Jingyi,Stahl, Shannon S.
-
supporting information
p. 6416 - 6419
(2016/06/09)
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- Copper-Catalyzed Aerobic Oxidative Amidation of Benzyl Alcohols
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A Cu-catalyzed synthesis of amides from alcohols and secondary amines using the oxygen in air as the terminal oxidant has been developed. The methodology is operationally simple requiring no high pressure equipment or handling of pure oxygen. The commercially available, nonprecious metal catalyst, Cu(phen)Cl2, in conjunction with di-tert-butyl hydrazine dicarboxylate and an inorganic base provides a variety of benzamides in moderate to excellent yields. The pKa of amine conjugate acid and electronics of alcohol were shown to impact the selection of base for optimal reactivity. A mechanism consistent with the observed reactivity trends, KIE, and Hammett study is proposed.
- Krabbe, Scott W.,Chan, Vincent S.,Franczyk, Thaddeus S.,Shekhar, Shashank,Napolitano, José G.,Presto, Carmina A.,Simanis, Justin A.
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p. 10688 - 10697
(2016/11/29)
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- Anionic phenoxy-amido rare-earth complexes as efficient catalysts for amidation of aldehydes with amines
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A series of anionic organo-rare-earth amido complexes stabilized by dianionic phenoxy-amido ligands were prepared and their catalytic behavior for amidation reactions of aldehydes with amines was elucidated. Amine elimination reaction of Ln[N(SiMe3)2]3(μ-Cl)Li(THF)3 with an equimolar of lithium aminophenoxy {[HNO]1Li(THF)}2, which was prepared by the reaction of [HNOH]1 {[HNOH]1 = N-p-fluoro-phenyl(2-hydroxy-3,5-di-tert-butyl)benzylamine} with one equivalent of n-BuLi in tetrahydrofuran (THF) in situ, gave the anionic phenoxy-amido rare earth amido complexes [NO]12Ln[N(SiMe3)2][Li(THF)]2 [Ln = Y (1), Yb (2), Sm (3), Nd (4)] in high isolated yields. Similar reactions of Ln[N(SiMe3)2]3(μ-Cl)Li(THF)3 with {[HNO]2Li(THF)}2, and {[HNO]3Li(THF)}2 in THF gave the anionic rare-earth amides [NO]22Ln[N(SiMe3)2][Li(THF)]2 [Ln = Sm (5), Nd (6)] and [NO]32Ln[N(SiMe3)2][Li(THF)]2 [Ln = Sm (7), Nd (8)] {[HNOH]2 = N-p-chloro-phenyl(2-hydroxy-3,5-di-tert-butyl)benzylamine; [HNOH]3 = N-p-bromo-phenyl(2-hydroxy-3,5-di-tert-butyl)benzylamine}, respectively. All of these complexes were fully characterized. X-ray structural determination revealed that these complexes are isostructural, and have solvated monomeric structures. Each of the rare-earth ions is coordinated by two phenoxy-amido ligands and one N(SiMe3)2 group, and the coordination geometry can be described as a distorted trigonal bipyramid. Each of the lithium atoms is surrounded by one aryloxo group, one amido group and one THF molecule, and the coordination geometry can be described as a trigonal plane. The catalytic behavior of these rare-earth amides for the amidation reaction of aldehyde with amine was elucidated. It was found that these complexes are efficient catalysts for this transformation to produce amides in good to excellent yields under mild reaction conditions, and in some cases, diacylamide compounds can be prepared conveniently.
- Wang, Chao,Huang, Lingling,Lu, Min,Zhao, Bei,Wang, Yaorong,Zhang, Yong,Shen, Qi,Yao, Yingming
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p. 94768 - 94775
(2015/11/24)
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- Mild and selective Et2Zn-catalyzed reduction of tertiary amides under Hydrosilylation conditions
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Diethylzinc (Et2Zn) can be used as an efficient and chemoselective catalyst for the reduction of tertiary amides under mild reaction conditions employing cost-effective polymeric silane (PMHS) as the hydride source. Crucial for the catalytic activity was the addition of a substoichiometric amount of lithium chloride to the reaction mixture. A series of amides containing different additional functional groups were reduced to their corresponding amines, and the products were isolated in good-to-excellent yields.
- Kovalenko, Oleksandr O.,Volkov, Alexey,Adolfsson, Hans
-
supporting information
p. 446 - 449
(2015/03/05)
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- Palladium-catalyzed aminocarbonylation of N-chloroamines with boronic acids
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Abstract Aryl (pseudo)halide-based (C-X) carbonylation reactions have been extensively studied during the past few decades. From both academic and synthetic points of view, the carbonylative transformation of N-X bonds represents an interesting and attractive area of investigation. In light of this, the first carbonylative cross-coupling between N-chloroamines and organoboronic acids has been developed. This new type of aminocarbonylation proceeds at mild temperatures (45-55 °C) with 2 mol % Pd/C (10 wt %) as the ligand-free catalyst. Not only arylboronic acids, but also alkenyl- and alkylboronic acids can be applied as the substrates and bromide and iodide substituents in the substrates are well tolerated. Initial mechanistic investigations have also been performed. Umpolung aminocarbonylation: The first palladium-catalyzed carbonylative cross-coupling between N-chloroamines and organoboronic acids has been realized. Various amides were isolated in moderate to excellent yields from reactions under mild temperatures with ligand-free Pd/C as the catalyst. Not only arylboronic acids, but also alkenyl- and alkylboronic acids are applied as the substrates and bromide and iodide substituents in the substrates are well tolerated.
- Li, Wanfang,Wu, Xiao-Feng
-
supporting information
p. 7374 - 7378
(2015/05/27)
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- Iron-catalyzed direct synthesis of amides from methylarenes
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An efficient, green and first catalytic process has been developed for the direct synthesis of amides from readily available petroleum by-products (methylarenes) and amines using an iron catalyst. In this new catalytic reaction, the methyl group of the me
- Srinivas Kotha, Surya,Badigenchala, Sindhura,Sekar, Govindasamy
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p. 1437 - 1445
(2015/05/19)
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- Copper-catalyzed one-pot synthesis of α-ketoamides from 1-arylethanols
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A copper-catalyzed one-pot strategy for the synthesis of α-ketoamides from 1-arylethanols is described. This triple oxidation of 1-arylethanols involves alcohol oxidation, sp3 C-H oxidation, and oxidative amidation with amines. The protocol is highly efficient, delivering α-ketoamides in good to excellent yields.
- Sharma, Nidhi,Kotha, Surya Srinivas,Lahiri, Nabajit,Sekar, Govindasamy
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p. 726 - 736
(2015/04/14)
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- Double carbonylation of aryl iodides with amines under an atmospheric pressure of carbon monoxide using sulfur-modified Au-supported palladium
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A double carbonylation of aryl iodides with amines proceeded smoothly under an atmospheric pressure of carbon monoxide by using palladium nanoparticles (Pd NPs) leached from a sulfur-modified Au-supported palladium material (SAPd), producing α-ketoamides in good to excellent yields. This journal is
- Saito, Nozomi,Taniguchi, Takahisa,Hoshiya, Naoyuki,Shuto, Satoshi,Arisawa, Mitsuhiro,Sato, Yoshihiro
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supporting information
p. 2358 - 2361
(2015/04/22)
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- Comparison of aminolysis of 2-pyridyl and 4-pyridyl x-substituted benzoates in acetonitrile: Evidence for a concerted mechanism involving a cyclic transition state
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A kinetic study on reactions of 2-pyridyl X-substituted benzoates (6a-i) with a series of cyclic secondary amines in MeCN is reported. The Hammett plot for the reaction of 6a-i with piperidine consists of two intersecting straight lines while the Yukawa-Tsuno plot exhibits an excellent linear correlation with ρX = 1.28 and r = 0.63, indicating that the nonlinear Hammett plot is not caused by a change in the rate-determining step but rather by resonance stabilization of substrates possessing an electron-donating group (EDG) in the benzoyl moiety. The Bronsted-type plots are linear with βnuc = 0.59 ± 0.02, which is typical of reactions reported to proceed through a concerted mechanism. A cyclic transition state (TS), which forces the reaction to proceed through a concerted mechanism, is proposed. The deuterium kinetic isotope effect of 1.3 ± 0.1 is consistent with the proposed mechanism. Analysis of activation parameters reveals that ΔH? increases linearly as the substituent X changes from an electron-withdrawing group (EWG) to an EDG, while TΔS ? remains nearly constant with a large negative value. The constant TΔS? value further supports the proposal that the reaction proceeds through a concerted mechanism with a cyclic TS.
- Um, Ik-Hwan,Bae, Ae-Ri,Um, Tae-Il
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p. 1206 - 1212
(2014/03/21)
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- Kinetic study on aminolysis of y-substituted-phenyl x-substituted- benzoates: Effects of substituents x and y on reactivity and reaction mechanism
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A kinetic study on aminolysis of 2-chloro-4-nitrophenyl X-substituted-benzoates (2a-k) in 80 mol % H2O/20 mol % DMSO at 25.0 oC is reported. The Bronsted-type plot for the reactions of 2-chloro-4-nitrophenyl benzoate (2g) with a series of cyclic secondary amines curves downward (e.g., β1 = 0.25, β2 = 0.85 and pKa o = 10.3), which is typical of reactions reported to proceed through a stepwise mechanism with a change in ratedetermining step (RDS). The Hammett plot for the reactions of 2a-k with piperidine consists of two intersecting straight lines, while the corresponding Yukawa-Tsuno plot exhibits an excellent linear correlation with ρX = 1.15 and r = 0.59. Thus, it has been concluded that the nonlinear Hammett plot is not due to a change in RDS but is caused by stabilization of substrates through resonance interactions between the electron-donating substituent and the C=O bond. Substrates possessing a substituent at the 2-position of the leaving aryloxide deviate negatively from the curved Bronsted-type plot for the reactions of Y-substituted-phenyl benzoates (3ai), implying that the steric hindrance exerted by the substituent at the 2-position is an important factor which governs the reactivity of Y-substituted-phenyl benzoates.
- Jeon, Seong Hoon,Kim, Hyun Soo,Han, Young Joon,Kim, Min-Young,Um, Ik-Hwan
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p. 471 - 476
(2014/03/21)
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- Silica nanosphere-supported palladium(II) furfural complex as a highly efficient and recyclable catalyst for oxidative amination of aldehydes
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The present work reports the fabrication of a novel and highly efficient silica nanospheres-based palladium catalyst (SiO2@APTES@Pd-FFR) via immobilization of a palladium complex onto silica nanospheres functionalized with 3-aminopropyltriethoxysilane (APTES), and its catalytic application for the oxidative amination of aldehydes to yield commercially important amides. The structure of the nano-catalyst was confirmed by Solid-state 13C CPMAS and 29Si CPMAS NMR spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier transform infrared spectroscopy (FT-IR), Energy dispersive X-ray fluorescence spectroscopy (ED-XRF), Atomic absorption spectroscopy (AAS), Transmission electron microscopy (TEM) and elemental analysis. The nano-catalyst was found to be highly effective for the oxidative amination of aldehydes using hydrogen peroxide as an environmentally benign oxidant to give amides. The effect of various reaction parameters such as temperature, amount of catalyst, reaction time, type of solvent, oxidant used, substrate to oxidant ratio etc. have been demonstrated to achieve high catalytic efficacy. Moreover, this nanostructured catalyst could be recovered with simplicity and reused for several cycles without any significant loss in its catalytic activity. In addition, the stability of the reused nano-catalyst was proved by FT-IR and HRTEM techniques. It is worth noting that the features of mild reaction conditions, simple work-up procedure, high product yield, no use of toxic organic solvents, high turn-over frequency (TOF), and easy recovery and reusability of the present quasi-homogeneous nano-catalyst make this protocol an attractive alternative to the existing catalytic methods for the oxidative amination of aldehydes to furnish industrially important amides. The Royal Society of Chemistry 2014.
- Sharma,Sharma, Shivani
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p. 1292 - 1304
(2014/01/06)
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- Catalytic bio-chemo and bio-bio tandem oxidation reactions for amide and carboxylic acid synthesis
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A catalytic toolbox for three different water-based one-pot cascades to convert aryl alcohols to amides and acids and cyclic amines to lactams, involving combination of oxidative enzymes (monoamine oxidase, xanthine dehydrogenase, galactose oxidase and laccase) and chemical oxidants (TBHP or CuI(cat)/H2O2) at mild temperatures, is presented. Mutually compatible conditions were found to afford products in good to excellent yields. This journal is
- Bechi, Beatrice,Herter, Susanne,McKenna, Shane,Riley, Christopher,Leimkühler, Silke,Turner, Nicholas J.,Carnell, Andrew J.
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supporting information
p. 4524 - 4529
(2014/12/11)
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- Efficient metal-free hydrosilylation of tertiary, secondary and primary amides to amines
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Hydrosilylation of secondary and tertiary amides to amines is described using catalytic amounts of B(C6F5)3. The organic catalyst enables the reduction of amides with cost-efficient, non-toxic and air stable PMHS and TMDS hydrosilanes. The methodology was successfully extended to the more challenging reduction of primary amides.
- Blondiaux, Enguerrand,Cantat, Thibault
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supporting information
p. 9349 - 9352
(2014/08/05)
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- Synthesis, crystal structure and anti-fatigue effects of some benzamide derivatives
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A series of benzamide derivatives such as 1-(1,3-benzodioxol-5-ylcarbonyl) piperidine (1-BCP) were synthesized by the reaction of substituted benzoic acids with piperidine, morpholine or pyrrolidine using a novel method. The crystals of these benzamide de
- Wu, Xianglong,Fan, Wutu,Pan, Yalei,Zhai, Yuankun,Niu, Yinbo,Li, Chenrui,Mei, Qibing
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p. 1034 - 1046
(2014/02/14)
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- Kinetic study on aminolysis of 2-chloro-4-nitrophenyl x-substituted-benzoates in acetonitrile and in H2O Containing 20mol% DMSO: Effects of medium and substituent X on reactivity and reaction mechanism
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Second-order rate constants for reactions of 2-chloro-4-nitrophenyl X-substituted-benzoates 1a-1j with a series of cyclic secondary amines in MeCN have been measured. Comparison of the kinetic results with those reported previously for the corresponding reactions carried out in H2O containing 20 mol % DMSO has revealed that amines are less reactive in MeCN. The Bronsted-type plot for the aminolysis of 2-chloro-4-nitrophenyl benzoate (1f) in MeCN is linear with βnuc= 0.64, which is in contrast to the curved Bronsted-type plot reported for the reaction performed in the H2O-DMSO misxture. The Hammett plot for the reactions of 1a-1j with piperidine consists of two intersecting straight lines while the Yukawa-Tsuno plot exhibits an excellent linear correlation with ρX= 1.22 and r = 0.60, indicating that the nonlinear Hammett plot is not due to a change in rate-determining step but is caused by stabilization of substrates possessing an electron-donating substituent through resonance interactions between the substituent and the carbonyl functionality. It has been concluded that medium change from the H2O-DMSO mixture to MeCN forces the aminolysis of 1a-1j to proceed through a concerted mechanism by destabilizing the zwitterionic tetrahedral intermediate (T±).
- Kim, Ha-Ram,Yoon, Jung Hwan,Kim, Min-Young,Um, Ik-Hwan
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supporting information
p. 922 - 927
(2015/02/19)
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- Facile and efficient KOH-catalysed reduction of esters and tertiary amides
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Esters and tertiary amides were efficiently reduced to their corresponding alcohols and amines in high yields under mild and environmentally friendly conditions. The presented KOH-catalysed system involves a simple hydrosilylation procedure that is carried out under solvent-free conditions and does not require the use of inert conditions.
- Fernandez-Salas, Jose A.,Manzini, Simone,Nolan, Steven P.
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p. 9758 - 9760
(2013/10/21)
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- Cesium carbonate-catalyzed reduction of amides with hydrosilanes
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Cesium carbonate has been found to be an effective catalyst for the reduction of tertiary carboxamides with the simple, commercially available PhSiH3 under solvent-free conditions. The catalytic system can effectively reduce a range of amides under relatively mild conditions (from room temperature to 80 C) to yield the corresponding amines in good to excellent yields (71-100%) and thus has the potential for practical applications.
- Xie, Weilong,Zhao, Mengdi,Cui, Chunming
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p. 7440 - 7444
(2014/04/03)
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- Chemical conversion of β-O-4 lignin linkage models through Cu-catalyzed aerobic amide bond formation
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Methods for conversion of the lignin β-O-4 models into amide derivatives and phenols have been developed, which is achieved via chemo-selective oxidation of the secondary benzylic alcohol and subsequent Cu-catalyzed aerobic amide bond formation.
- Zhang, Jian,Liu, Yu,Chiba, Shunsuke,Loh, Teck-Peng
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supporting information
p. 11439 - 11441
(2013/12/04)
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- The direct amidation of α-diketones with amines via TBHP-promoted oxidative cleavage of C(sp2)-C(sp2) bonds
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A novel and efficient direct amidation of α-diketones with amines via TBHP-promoted oxidative cleavage of C(sp2)-C(sp2) bonds has been developed. The strategy provides an alternative approach to amides under metal-free conditions.
- Zhao, Qiong,Li, Hongji,Wang, Lei
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supporting information
p. 6772 - 6779
(2013/10/01)
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- Facile preparation of amides from carboxylic acids and amines with ion-supported Ph3P
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Ion-supported Ph3P, 4-(diphenylphosphino)benzyltrimethylammonium bromide (IS-Ph3P), could be used for the facile amidation of a wide range of carboxylic acids with amines in the presence of bromotrichloromethane to provide the corresponding amides in good yields. In the present reaction, the desired amides were obtained in good yields with high purity by simple extraction of the reaction mixture with diethyl ether or chloroform and subsequent removal of the solvent from the extract. Moreover, ion-supported Ph3PO (IS-Ph3PO), which was a co-product derived from IS-Ph3P in the present reductive condensation, was recovered in high yield and could be reduced to IS-Ph3P for reuse in the same amidation of carboxylic acid.
- Kawagoe, Yuhsuke,Moriyama, Katsuhiko,Togo, Hideo
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p. 3971 - 3977
(2013/06/27)
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- Aerobic oxidative amidation of aromatic and cinnamic aldehydes with secondary amines by CuI/2-pyridonate catalytic system
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A simple and convenient CuI/2-pyridonate catalytic system for the oxidative amidation of aldehydes with secondary amines has been developed. With this system, a variety of useful arylamides have been synthesized in moderate to good yields in the presence of small amount of copper catalyst and the pyridonate ligand, generating only water as a coproduct. Synthesis of cinnamamides was also achieved by the reactions of cinnamaldehydes with secondary amines in moderate yields. Air was successfully employed as a green oxidant in this catalytic system, achieving a safe and atom-efficient system for the synthesis of amides.
- Zhu, Mingwen,Fujita, Ken-Ichi,Yamaguchi, Ryohei
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p. 9102 - 9109,8
(2012/12/11)
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- Yttrium (amidate) complexes for catalytic C-N bond formation. Rapid, room temperature amidation of aldehydes
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Yttrium (amidate) precatalysts are highly active for the mild amidation of aldehydes with amines. Reactions occur at room temperature within 5 min in up to 98% isolated yield. These rare-earth systems are effective for this transformation in the absence of supplementary heat, light, base, or oxidants. The reaction proceeds with functionalized amines and/or aldehydes. A comparison of various amidate precatalysts in combination with reaction monitoring suggests that the targeted amide products formed during the reaction promote the formation of alternative catalytically active amidate species in situ.
- Thomson, Jaclyn A.,Schafer, Laurel L.
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experimental part
p. 7897 - 7904
(2012/08/07)
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- Copper-catalyzed aerobic oxidative synthesis of α-ketoamides from methyl ketones, amines and NIS at room temperature
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A simple, efficient and practical copper-catalyzed aerobic oxidative synthesis of α-ketoamides from aryl methyl ketones, aliphatic amines and N-iodosuccinimide (NIS) has been developed. The one-pot reaction may proceed smoothly at room temperature in the open air. The possible mechanism for the formation of α-ketoamides was proposed. Molecular oxygen in air functions as both an oxidant and an oxygen source.
- Zhang, Juan,Wei, Ying,Lin, Shaoxia,Liang, Fushun,Liu, Pengjun
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p. 9237 - 9242
(2013/01/15)
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