- Copper-Catalyzed Carbonylative Coupling of Cycloalkanes and Amides
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Carbonylation reactions are a most powerful method for the synthesis of carbonyl-containing compounds. However, most known carbonylation procedures still require noble-metal catalysts and the use of activated compounds and good nucleophiles as substrates.
- Li, Yahui,Dong, Kaiwu,Zhu, Fengxiang,Wang, Zechao,Wu, Xiao-Feng
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- Nickel-Catalyzed Reductive Cross-Coupling of N-Acyl and N-Sulfonyl Benzotriazoles with Diverse Nitro Compounds: Rapid Access to Amides and Sulfonamides
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Herein we report a Ni-catalyzed reductive transamidation of conveniently available N-acyl benzotriazoles with alkyl, alkenyl, and aryl nitro compounds, which afforded various amides with good yields and a broad substrate scope. The same catalytic reaction conditions were also applicable for N-sulfonyl benzotriazoles, which could undergo smooth reductive coupling with nitroarenes and nitroalkanes to afford the corresponding sulfonamides.
- Qu, Erdong,Li, Shangzhang,Bai, Jin,Zheng, Yan,Li, Wanfang
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supporting information
p. 58 - 63
(2021/12/27)
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- Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
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Oximes are valuable synthetic intermediates for the preparation of a variety of functional groups. To date, the stereoselective synthesis of oximes remains a major challenge, as most current synthetic methods either provide mixtures of E and Z isomers or furnish the thermodynamically preferred E isomer. Herein we report a mild and general method to achieve Z isomers of aryl oximes by photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmann rearrangement that enables novel reactivity with alkyl groups migrating preferentially over aryl groups, reversing the regioselectivity of the traditional Beckmann reaction. Chemodivergent N- or O- cyclizations of alkenyl oximes are also demonstrated, leading to nitrones or cyclic oxime ethers, respectively.
- Zhang, Xiao,Rovis, Tomislav
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p. 21211 - 21217
(2021/12/27)
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- Preparation method of amide
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The invention relates to a preparation method of an amide, wherein, under the action of oxygen, the isothiocyanate and the aldehyde can react to form an amide, and the reaction temperature can be effectively increased only when not less than 110 °C. This process is also suitable for the reaction of isocyanates with aldehydes to produce amides. The preparation method is cheap in raw material, wide in substrate application range and free of metal catalysts in the reaction process. The initiator or other activator is green and economical, and can effectively reduce the cost.
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Paragraph 0055-0079; 0188-0193
(2021/08/25)
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- Method for promoting acylation of amine or alcohol by carbon dioxide
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The invention relates to a method for promoting acylation of amine or alcohol by carbon dioxide, which comprises the following steps of: mixing an amine compound, carboxylate or thiocarboxylate compound and a reaction solvent under the action of carbon dioxide, and reacting to obtain an amide compound, or under the action of carbon dioxide, mixing the alcohol compound, the thiocarboxylate compound and the reaction solvent [gamma]-valerolactone, and reacting to obtain the ester compound. According to the invention, under the promotion action of carbon dioxide, carboxylate or thiocarboxylate is used as an acylation reagent, and amine and alcohol are converted into amide and ester compounds in the absence of a transition metal catalyst, so that acylation reagents such as acyl chloride or anhydride with irritation and corrosivity are avoided; and the method has the advantages of simple operation, mild reaction conditions, high tolerance of substrate functional groups, strong applicability and high yield, and provides an efficient, reliable and economical preparation method for synthesis of amide and ester compounds.
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Paragraph 0033-0034
(2021/05/29)
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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.
- Bera, Jitendra K.,Pandey, Pragati
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supporting information
p. 9204 - 9207
(2021/09/20)
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- Visible-Light-Promoted Iron-Catalyzed N-Arylation of Dioxazolones with Arylboronic Acids
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A visible-light-promoted and simple iron salt-catalyzed N-arylation was achieved efficiently under external photosensitizer-free conditions. Arylboronic acids and bench-stable dioxazolones were used for this cross-coupling reaction. This reaction features high reactivity, wide substrate scope, good functional group tolerance, simple operation procedure, and mild reaction conditions. Preliminary mechanistic investigations were conducted to support a radical pathway. This method may contribute to shift the paradigm of iron-catalyzed C-N bond construction and nitrene transfer chemistry.
- Tang, Jing-Jing,Yu, Xiaoqiang,Yamamoto, Yoshinori,Bao, Ming
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p. 13955 - 13961
(2021/11/20)
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- An Environmentally Benign, Catalyst-Free N?C Bond Cleavage/Formation of Primary, Secondary, and Tertiary Unactivated Amides
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Herein, we report an operationally simple, cheap, and catalyst-free method for the transamidation of a diverse range of unactivated amides furnishing the desired products in excellent yields. This protocol is environmentally friendly and operates under extremely mild conditions without using any promoter or additives. Significantly, this strategy has been implied in the chemoselective synthesis of a pharmaceutical molecule, paracetamol, on a gram-scale with excellent yield. We anticipate that this universally applicable strategy will be of great interest in drug discovery, biochemistry, and organic synthesis.
- Kumar, Vishal,Dhawan, Sanjeev,Girase, Pankaj Sanjay,Singh, Parvesh,Karpoormath, Rajshekhar
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p. 5627 - 5639
(2021/11/11)
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- NaOTs-promoted transition metal-free C-N bond cleavage to form C-X (X = N, O, S) bonds
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Multifunctional transformation of amide C-N bond cleavage is reported. The protocol applies to benzamide, thioamide, alcohols, and mercaptan under similar reaction conditions catalyzed by NaOTs. It is noteworthy that NaOTs can not only be recycled and reused for up to three cycles without significant loss in catalytic activity, but also catalyze gram-grade reactions. This study provides a novel solution with mild conditions and a simple procedure for transformation of multiple amides.
- Chen, Wei,Liu, Sicheng,Liu, Tingting,Majeed, Irfan,Ye, Xiaojing,Zeng, Zhuo,Zhang, Yuqi,Zhu, Yulin
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supporting information
p. 8566 - 8571
(2021/10/20)
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- Photoinduced Carbamoylation of C(sp3)H Bonds with Isocyanates
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Alkylbenzenes coupled with isocyanates at the benzylic position upon irradiation with visible light in the presence of an iridium photoredox catalyst, a bromide anion, and a nickel catalyst, producing N-substituted α-aryl amides. An analogous carbamoylation reaction of aliphatic CH bonds of alkanes took place when UV light and a diaryl ketone were used instead of visible light and the iridium complex. The present reaction offers a straightforward and atom-economical method for the synthesis of carboxamides starting from hydrocarbons with one-carbon extension.
- Ishida, Naoki,Kawasaki, Tairin,Murakami, Masahiro,Tomono, Ryota,Yamazaki, Katsushi
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supporting information
p. 1684 - 1684
(2021/09/16)
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- Iron-catalyzed oxidative amidation of acylhydrazines with amines
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A new approach for amide bond formation via a mild and efficient Iron-catalyzed cross-coupling reaction of acylhydrazines and amines using TBHP as oxidant is described. This protocol is compatible with a wide range of amines and acylhydrazines. In addition, the synthetic application of the reaction is presented.
- Wang, Yi-Jie,Zhang, Guo-Yu,Shoberu, Adedamola,Zou, Jian-Ping
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supporting information
(2021/08/18)
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- Practical one-pot amidation of N -Alloc-, N -Boc-, and N -Cbz protected amines under mild conditions
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A facile one-pot synthesis of amides from N-Alloc-, N-Boc-, and N-Cbz-protected amines has been described. The reactions involve the use of isocyanate intermediates, which are generated in situ in the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, to react with Grignard reagents to produce the corresponding amides. Using this reaction protocol, a variety of N-Alloc-, N-Boc-, and N-Cbz-protected aliphatic amines and aryl amines were efficiently converted to amides with high yields. This method is highly effective for the synthesis of amides and offers a promising approach for facile amidation.
- Hong, Wan Pyo,Tran, Van Hieu,Kim, Hee-Kwon
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p. 15890 - 15895
(2021/05/19)
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- Fe-mediated synthesis of: N -aryl amides from nitroarenes and acyl chlorides
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Amides are prevalent in nature and valuable functional compounds in agrochemical, pharmaceutical, and materials industries. In this work, we developed a selective and mild method for the synthesis of N-aryl amides. Starting from commercially available nitroarenes and acyl halides, N-aryl amides with good yields can be obtained in water. Especially in the process of transformation, Fe dust is the only reductant and additive, and the reaction can be easily performed on a large scale.
- Wu, Yundong,Guo, Lei,Liu, Yuxuan,Xiang, Jiannan,Jiang, Jun
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p. 15290 - 15295
(2021/05/19)
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- Chromium-catalyzed ligand-free amidation of esters with anilines
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Amides are important structural motifs in pharmaceutical and agrochemical chemistry because of the intriguing biological active properties. We report here the amidation of commercially available esters with anilines that was promoted by low-cost and air-stable chromium(III) pre-catalyst combined with magnesium, providing access to amides. This reaction occurs without the use of external ligands in a simple operation. Mechanistic studies indicate that a reactive aminated Cr species responsible for the amidation can be considered, which may be formed by reaction of low-valent Cr with aniline followed by reduction with hydrogen evolution.
- Chen, Changpeng,Ling, Liang,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 762 - 766
(2021/04/14)
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- Beckmann rearrangement of ketoximes promoted by cyanuric chloride and dimethyl sulfoxide under a mild condition
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Synthesis of amides via Beckmann rearrangement of ketoximes promoted by cyanuric chloride (TCT)/DMSO under mild conditions has been reported. Conditions of the Beckmann rearrangement, e.g., solvents, the ratios of TCT/DMSO, and the temperature, were investigated using diphenylmethanone oxime as a substrate. The optimized conditions were adopted to afford fourteen amides with yields ranging from 20% to 99%. A plausible mechanism involving an active dimethyl alkoxysulfonium intermediate was proposed according to the mass spectrometry analysis. To our best knowledge, this is the first case of study on Beckmann rearrangement of ketoximes promoted by TCT/DMSO under a mild condition to afford amides efficiently.
- Ma, Ruonan,Chen, Xueyuan,Xiao, Zhiyin,Natarajan, Mookan,Lu, Chunxin,Jiang, Xiujuan,Zhong, Wei,Liu, Xiaoming
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supporting information
(2021/01/06)
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- A practical and sustainable protocol for direct amidation of unactivated esters under transition-metal-free and solvent-free conditions
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In this paper, a NaOtBu-mediated synthesis approach was developed for direct amidation of unactivated esters with amines under transition-metal-free and solvent-free conditions, affording a series of amides in good to excellent yields at room temperature. In particular, an environmentally friendly and practical workup procedure, which circumvents the use of organic solvents and chromatography in most cases, was disclosed. Moreover, the gram-scale production of representative products3a,3wand3auwas efficiently realized by applying operationally simple, sustainable and practical procedures. Furthermore, this approach was also applicable to the synthesis of valuable molecules such as moclobemide (a powerful antidepressant), benodanil and fenfuram (two commercial agricultural fungicides). These results demonstrate that this protocol has the potential to streamline amide synthesis in industry. Meanwhile, quantitative green metrics of all the target products were evaluated, implying that the present protocol is advantageous over the reported ones in terms of environmental friendliness and sustainability. Finally, additional experiments and computational calculations were carried out to elucidate the mechanistic insight of this transformation, and one plausible mechanism was provided on the basis of these results and the related literature reports.
- Chen, Cheng,Cheng, Hua,Du, Min-Chen,Qian, Liang,Qin, Xin,Sang, Wei,Yao, Wei-Zhong,Yuan, Ye,Zhang, Rui
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supporting information
p. 3972 - 3982
(2021/06/17)
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- Solar and visible-light active nano Ni/g-C3N4photocatalyst for carbon monoxide (CO) and ligand-free carbonylation reactions
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In this study, we investigate the amino and alkoxycarbonylation reaction between various substituted aryl halides, benzyl iodides, and iodocyclohexane with different types of amines and alcohols in the absence of carbon monoxide gas and ligands. Similar reactions are carried out at high temperatures, in the presence of appropriate ligands, stoichiometric amounts of bases, and gaseous carbon monoxide, which endanger the health of organic chemists. We present a novel method that does not utilize ligands, bases, gaseous CO, and special conditions. This procedure is a redox reaction carried out by new economic nano Ni/g-C3N4at room temperature and under visible light. Mo(CO)6was used toin situgenerate CO, to resolve the problems caused by the use of CO gas. This protocol has the ability to be used on a gram scale by using a continuous flow reactor.
- Hosseini-Sarvari, Mona,Akrami, Zahra
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p. 956 - 969
(2021/02/26)
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- Direct synthesis of secondary amides from ketones through Beckmann rearrangement using O-(mesitylsulfonyl)hydroxylamine
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The Beckmann rearrangement is a versatile method for the preparation of secondary amides from ketones via oxime intermediates and has been widely used in the synthesis of bioactive natural products and pharmaceuticals. Herein, we have developed a highly efficient direct method for the preparation of secondary amides and lactams from ketones using O-(mesitylsulfonyl)hydroxylamine (MSH). The reactions proceed rapidly at room temperature under mild condition without requiring any additive, and tolerate multiple functional groups. A simple aqueous work-up often furnished the products in excellent yield with high purity.
- Chandra, Dinesh,Verma, Saumya,Pandey, Chandra Bhan,Yadav, Ajay K.,Kumar, Puneet,Tiwari, Bhoopendra,Jat, Jawahar L.
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supporting information
(2020/03/23)
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- Catalyst- And oxidant-free electrochemical: para -selective hydroxylation of N -arylamides in batch and continuous-flow
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Hydroxyl compounds serve as key building blocks in the preparation of biologically active natural products and drugs. Traditionally, hydroxylation of the aromatic ring is achieved using stoichiometric amounts of oxidants, which leads to low atom-economy, undesired by-products, potential explosion risk and environmental pollution. Recently, electrosynthesis has attracted increasing attention as it employs clean electrical energy to promote redox reactions avoiding the use of oxidants. However, due to the poor mass and heat transfers of batch cells, low productivity and selectivity limit its further application. Herein, we develop a catalyst-, oxidant-, acidic solvent- and quaternary ammonium salt-free electrochemical para-selective hydroxylation of N-arylamides at room temperature in batch and continuous-flow. This proposal features excellent position control and water, air and functional group tolerance. Also, it is easy to scale up with higher productivity and selectivity using a flow electrolysis cell.
- Chen, Meng-Yi,Fang, Zheng,Guo, Kai,Lin, Xin-Xin,Liu, Cheng-Kou
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supporting information
p. 6437 - 6443
(2020/11/09)
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- Synthesis of Aliphatic Amides through a Photoredox Catalyzed Radical Carbonylation Involving Organosilicates as Alkyl Radical Precursors
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Alkyl radicals, from primary to tertiary, formed by photocatalyzed oxidation of organosilicates, are involved efficiently in radical carbonylation with carbon monoxide (CO), in the presence of various amines and CCl4, leading to a variety of amides in moderate to good yields. (Figure presented.).
- Cartier, Alex,Levernier, Etienne,Dhimane, Anne-Lise,Fukuyama, Takahide,Ollivier, Cyril,Ryu, Ilhyong,Fensterbank, Louis
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p. 2254 - 2259
(2020/05/06)
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- Visible Light-Induced Amide Bond Formation
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A metal-, base-, and additive-free amide bond formation reaction was developed under an organic photoredox catalyst. This green approach showed excellent functional selectivity without affecting other functional groups such as alcohols, phenols, ethers, esters, halogens, or heterocycles. This method featured a broad substrate scope, good compatibility with water and air, and high yields (≤95%). The potential utilities were demonstrated by the synthesis of important drug molecules such as paracetamol, melatonin, moclobemide, and acetazolamide.
- Song, Wangze,Dong, Kun,Li, Ming
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supporting information
p. 371 - 375
(2019/11/29)
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- Method for preparing amide by visible light-induced metal-free participation (by machine translation)
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The method for preparing the amide in the, preparation method of the novel amide disclosed by the invention has the advantages that, the reaction: conditions are mild, the 9 - reaction conditions are mild, and the yield 71%. of the reaction conditions is not lower than the reaction conditions . (by machine translation)
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Paragraph 0067-0070
(2020/02/14)
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- Zinc(II)-Catalyzed Synthesis of Secondary Amides from Ketones via Beckmann Rearrangement Using Hydroxylamine-O-sulfonic Acid in Aqueous Media
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A zinc(II)-catalyzed single-step protocol for the Beckmann rearrangement using hydroxylamine-O-sulfonic acid (HOSA) as the nitrogen source in water was developed. This direct method efficiently produces secondary amides under open atmosphere in a pure form after basic aqueous workup. It isenvironmentally benign and operationally simple.
- Verma, Saumya,Kumar, Puneet,Khatana, Anil K.,Chandra, Dinesh,Yadav, Ajay K.,Tiwari, Bhoopendra,Jat, Jawahar L.
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p. 3272 - 3276
(2020/11/02)
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- Tandem Photoredox Catalysis: Enabling Carbonylative Amidation of Aryl and Alkylhalides
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We report a new visible-light-mediated carbonylative amidation of aryl, heteroaryl, and alkyl halides. A tandem catalytic cycle of [Ir(ppy)2(dtb-bpy)]+ generates a potent iridium photoreductant through a second catalytic cycle in the presence of DIPEA, which productively engages aryl bromides, iodides, and even chlorides as well as primary, secondary, and tertiary alkyl iodides. The versatile in situ generated catalyst is compatible with aliphatic and aromatic amines, shows high functional-group tolerance, and enables the late-stage amidation of complex natural products.
- Connell, Timothy U.,Forni, José A.,Micic, Nenad,Polyzos, Anastasios,Weragoda, Geethika
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supporting information
p. 18646 - 18654
(2020/08/21)
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- Visible-light-induced Beckmann rearrangement by organic photoredox catalysis
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A facile and general strategy for efficient direct conversion of oximes to amides using an inexpensive organic photocatalyst and visible light is described. This radical Beckmann rearrangement can be performed under mild conditions. Various alkyl aryl ketoximes and diaryl ketoximes can be effectively converted into the corresponding amides in excellent yields.
- Tang, Li,Wang, Zhi-Lv,Wan, Hai-Lan,He, Yan-Hong,Guan, Zhi
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supporting information
p. 6182 - 6186
(2020/09/01)
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- An Electrochemical Beckmann Rearrangement: Traditional Reaction via Modern Radical Mechanism
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Abstract: Electrosynthesis as a potential means of introducing heteroatoms into the carbon framework is rarely studied. Herein, the electrochemical Beckmann rearrangement, i. e. the direct electrolysis of ketoximes to amides, is presented for the first time. Using a constant current as the driving force, the reaction can be easily carried out under neutral conditions at room temperature. Based on a series of mechanistic studies, a novel radical Beckmann rearrangement mechanism is proposed. This electrochemical Beckmann rearrangement does not follow the trans-migration rule of the classical Beckmann rearrangement.
- Tang, Li,Wang, Zhi-Lv,He, Yan-Hong,Guan, Zhi
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p. 4929 - 4936
(2020/08/21)
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- Synthetic method of amide compound
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The invention discloses a synthetic method of an amide compound. An organic carboxylic acid compound with the structure of a formula (I) and an amine compound with the structure of a formula (II) aresubjected to a grinding reaction to obtain the amide compound with the structure of a formula (III) in the presence of a coupling reagent. According to the synthetic method, a heat source is not required to be used for heating, and an organic solvent is also not required to be used as a medium, operation is easy, the reaction time is short, post-processing is easy, and industrial production is easy to achieve(Please see the specifications for the formulas).
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Paragraph 0087-0090
(2019/06/08)
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- Cu-mediated selective bromination of aniline derivatives and preliminary mechanism study
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A simple and efficient bromination of aniline, aniline derivatives, and analogs have been developed. Forty three examples were given and the highest yield reached was 98%. Different substrates including substituted aniline, pyridin-amine, N-substituted aniline, N,N-disubstituted aniline, N-phenyl-amide, N-phenyl-sulfonamide, and nitrogen-containing heterocycles were all reactive and selectively generated desired bromo-products. The method can be applied to synthesize drug intermediate and quinoxaline derivatives.
- Zhao, Hong-Yi,Yang, Xue-Yan,Lei, Hao,Xin, Minhang,Zhang, San-Qi
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supporting information
p. 1406 - 1415
(2019/05/01)
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- Synthesis of diverse libraries of carboxamides via chemoselective N-acylation of amines by carboxylic acids employing Br?nsted acidic IL [BMIM(SO3H)][OTf]
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Chemoselective N-acylation of amines with carboxylic acids as acyl electrophiles and Br?nsted acidic IL [BMIM(SO3H)][OTf] as promoter is reported under both thermal and microwave irradiation to produce libraries of carboxamides in good to excellent yields after a simple workup. The protocol is compatible with structurally diverse 1° and 2° amines and works in the presence of sensitive functional groups such as thiols and phenols. The potential for recycling and reuse of the IL is also demonstrated.
- Savanur, Hemantkumar M.,Malunavar, Shruti S.,Prabhala, Pavankumar,Sutar, Suraj M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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supporting information
(2019/09/30)
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- Photocatalytic Oxidative C-H Thiolation: Synthesis of Benzothiazoles and Sulfenylated Indoles
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We report studies on the photocatalytic formation of C-S bonds to form benzothiazoles via an intramolecular cyclization and sulfenylated indoles via an intermolecular reaction. Cyclic voltammetry (CV) and density functional theory studies suggest that benzothiazole formation proceeds via a mechanism that involves an electrophilic sulfur radical, while the indole sulfenylation likely proceeds via a nucleophilic sulfur radical adding into a radical cationic indole. These conditions were successfully extended to several thiobenzamides and indole substrates.
- Aceves, Ernesto Millan,Albright, Samuel T.,Cedano, Mario R.,Dinh, Andrew N.,Gustafson, Jeffrey L.,Nguyen, Ashley D.,Smith, Diane K.
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supporting information
p. 1648 - 1655
(2019/08/26)
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- Synergistic Copper-Catalyzed Reductive Aminocarbonylation of Alkyl Iodides with Nitroarenes
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We have developed a Cu-catalyzed reductive aminocarbonylation of alkyl iodides using nitroarenes as the nitrogen source. The reaction proceeds with a single copper catalyst playing dual roles of synergistically mediating both carbonylation of alkyl iodide
- Zhao, Siling,Mankad, Neal P.
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supporting information
p. 10106 - 10110
(2019/12/24)
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- Highly Chemoselective, Transition-Metal-Free Transamidation of Unactivated Amides and Direct Amidation of Alkyl Esters by N-C/O-C Cleavage
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The amide bond is one of the most fundamental functional groups in chemistry and biology and plays a central role in numerous processes harnessed to streamline the synthesis of key pharmaceutical and industrial molecules. Although the synthesis of amides is one of the most frequently performed reactions by academic and industrial scientists, the direct transamidation of tertiary amides is challenging due to unfavorable kinetic and thermodynamic contributions of the process. Herein, we report the first general, mild, and highly chemoselective method for transamidation of unactivated tertiary amides by a direct acyl N-C bond cleavage with non-nucleophilic amines. This operationally simple method is performed in the absence of transition metals and operates under unusually mild reaction conditions. In this context, we further describe the direct amidation of abundant alkyl esters to afford amide bonds with exquisite selectivity by acyl C-O bond cleavage. The utility of this process is showcased by a broad scope of the method, including various sensitive functional groups, late-stage modification, and the synthesis of drug molecules (>80 examples). Remarkable selectivity toward different functional groups and within different amide and ester electrophiles that is not feasible using existing methods was observed. Extensive experimental and computational studies were conducted to provide insight into the mechanism and the origins of high selectivity. We further present a series of guidelines to predict the reactivity of amides and esters in the synthesis of valuable amide bonds by this user-friendly process. In light of the importance of the amide bond in organic synthesis and major practical advantages of this method, the study opens up new opportunities in the synthesis of pivotal amide bonds in a broad range of chemical contexts.
- Li, Guangchen,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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supporting information
p. 11161 - 11172
(2019/08/07)
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- Method for preparing amide compounds
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The invention discloses a method for preparing amide compounds. The method comprises the step of subjecting organic carboxylate with a structure represented by a formula (I) shown in the description and an amine compound with a structure represented by a formula (II) shown in the description to a grinding reaction, thereby preparing an amide compound with a structure represented by a formula (III)shown in the description and an alcohol compound with a structure represented by a formula (IV) shown in the description. According to the synthesis method, a heat source is not required to supply heat, an organic solvent is not required to serve as a medium, the operation is simple, the reaction time is short, the aftertreatment is simple, and thus, industrial production is easy to achieve.
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Paragraph 0071-0074
(2019/06/05)
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- Amide Synthesis from Thiocarboxylic Acids and Amines by Spontaneous Reaction and Electrosynthesis
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Amide bond formation is one of the most important basic reactions in chemistry. A catalyst-free approach for constructing amide bonds from thiocarboxylic acids and amines was developed. The mechanistic studies showed that the disulfide was the key intermediate for this amide synthesis. Thiobenzoic acids could be automatically oxidized to disulfides in air, thioaliphatic acids could be electro-oxidized to disulfides, and the resulting disulfides reacted with amines to give the corresponding amides. By this method, various amides could be easily synthesized in excellent yields without using any catalyst or activator. The successful synthesis of bioactive compounds also highlights the synthetic utility of this strategy in medicinal chemistry.
- Tang, Li,Matuska, Jack H.,Huang, Yu-Han,He, Yan-Hong,Guan, Zhi
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p. 2570 - 2575
(2019/06/13)
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- Copper-Catalyzed Electrophilic Amidation of Organotrifluoroborates with Use of N-Methoxyamides
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A copper-catalyzed electrophilic amidation of aryltrifluoroborates with use of N-methoxyamides is reported. The reaction shows high functional group compatibility derived from two distinct features: 1) the high stability of the N-methoxyamides and 2) the nonbasic mild conditions in the presence of LiCl. The developed method can also be applied to the synthesis of enamides, which are widely distributed in natural products. Preliminary mechanistic studies suggest that the initial step is the transmetalation of the aryltrifluoroborate by the assistance of LiCl, and the resulting aryl copper intermediate provides the anilide through non-SN2 oxidative addition to the N-methoxyamide and subsequent reductive elimination.
- Banjo, Shona,Nakasuji, Eiko,Meguro, Tatsuhiko,Sato, Takaaki,Chida, Noritaka
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supporting information
p. 7941 - 7947
(2019/05/24)
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- Chromium-Catalyzed Activation of Acyl C-O Bonds with Magnesium for Amidation of Esters with Nitroarenes
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Here, we report a chromium-catalyzed activation of acyl C-O bonds with magnesium for amidation of esters with nitroarenes. Low-cost chromium(III) chloride shows high reactivity in promoting amidation by using magnesium as reductant and chlorotrimethylsilane as additive. It provides a step-economic strategy to the synthesis of centrally important amide motifs using inexpensive and air-stable nitroarenes as amino sources.
- Ling, Liang,Chen, Changpeng,Luo, Meiming,Zeng, Xiaoming
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supporting information
(2019/03/19)
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- Convenient metal-free direct oxidative amidation of aldehyde using dibromoisocyanuric acid under mild conditions
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A facile method for the direct synthesis of amides from aldehydes is described. Amide bonds were synthesized by an oxidative amidation in the presence of dibromoisocyanuric acid (DBI). Treatment of aromatic and aliphatic aldehydes with dibromoisocyanuric acid generated acyl bromide intermediates, which were employed to react with a variety of secondary and primary amines to give amides. Through this reaction method, various amides were synthesized directly from aldehydes under mild conditions in high yields and short times. This facile and efficient procedure provides potential strategy for the direct synthesis of amides from aldehydes.
- Kang, Soosung,La, Minh Thanh,Kim, Hee-Kwon
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supporting information
p. 3541 - 3546
(2018/08/29)
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- Scope and mechanism of a true organocatalytic beckmann rearrangement with a boronic acid/perfluoropinacol system under ambient conditions
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Catalytic activation of hydroxyl functionalities is of great interest for the production of pharmaceuticals and commodity chemicals. Here, 2-alkoxycarbonyl- and 2-phenoxycarbonyl-phenylboronic acid were identified as efficient catalysts for the direct and chemoselective activation of oxime N-OH bonds in the Beckmann rearrangement. This classical organic reaction provides a unique approach to prepare functionalized amide products that may be difficult to access using traditional amide coupling between carboxylic acids and amines. Using only 5 mol % of boronic acid catalyst and perfluoropinacol as an additive in a polar solvent mixture, the operationally simple protocol features mild conditions, a broad substrate scope, and a high functional group tolerance. A wide variety of diaryl, aryl-alkyl, heteroaryl-alkyl, and dialkyl oximes react under ambient conditions to afford high yields of amide products. Free alcohols, amides, carboxyesters, and many other functionalities are compatible with the reaction conditions. Investigations of the catalytic cycle revealed a novel boron-induced oxime transesterification providing an acyl oxime intermediate involved in a fully catalytic nonself-propagating Beckmann rearrangement mechanism. The acyl oxime intermediate was prepared independently and was subjected to the reaction conditions. It was found to be self-sufficient; it reacts rapidly, unimolecularly without the need for free oxime. A series of control experiments and 18O labeling studies support a true catalytic pathway involving an ionic transition structure with an active and essential role for the boronyl moiety in both steps of transesterification and rearrangement. According to 11B NMR spectroscopic studies, the additive perfluoropinacol provides a transient, electrophilic boronic ester that is thought to serve as an internal Lewis acid to activate the ortho-carboxyester and accelerate the initial, rate-limiting step of transesterification between the precatalyst and the oxime substrate.
- Mo, Xiaobin,Morgan, Timothy D. R.,Ang, Hwee Ting,Hall, Dennis G.
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p. 5264 - 5271
(2018/04/24)
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- Catalyst- and Supporting-Electrolyte-Free Electrosynthesis of Benzothiazoles and Thiazolopyridines in Continuous Flow
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A catalyst- and supporting electrolyte-free method for electrochemical dehydrogenative C?S bond formation in continuous flow has been developed. A broad range of N-arylthioamides have been converted to the corresponding benzothiazoles in good to excellent yields and with high current efficiencies. This transformation is achieved using only electricity and laboratory grade solvent, avoiding degassing or the use of inert atmosphere. This work highlights three advantages of electrochemistry in flow, which is (i) a supporting electrolyte-free reaction, (ii) an easy scale-up of the reaction without the need for a larger reactor and, (iii) the important and effective impact of having a good mixing of the reaction mixture, which can be achieved effectively with the use of flow systems. This clearly improves the reported methods for the synthesis of benzothiazoles.
- Folgueiras-Amador, Ana A.,Qian, Xiang-Yang,Xu, Hai-Chao,Wirth, Thomas
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supporting information
p. 487 - 491
(2017/12/15)
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- Direct and Catalytic Amide Synthesis from Ketones via Transoximation and Beckmann Rearrangement under Mild Conditions
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The Br?nsted acid-catalyzed synthesis of secondary amides from ketones under mild conditions is described via transoximation and Beckmann rearrangement using O-protected oximes as more stable equivalents of explosive O-protected hydroxylamines. This methodology could be applied to highly rearrangement-selective amide synthesis from α-branched alkyl aryl ketones and performed on a 1-g scale. The presence of water is essential for this reaction, and its role was clarified by isotope-labeling experiments.
- Hyodo, Kengo,Hasegawa, Genna,Oishi, Naoki,Kuroda, Kazuma,Uchida, Kingo
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p. 13080 - 13087
(2018/11/02)
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- Rh(CAAC)-Catalyzed Arene Hydrogenation: Evidence for Nanocatalysis and Sterically Controlled Site-Selective Hydrogenation
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We report the arene hydrogenation of ethers, amides, and esters at room temperature and low hydrogen pressure, starting from [(CAAC)Rh(COD)Cl] (CAAC = cyclic alkyl amino carbene). Kinetic, mechanistic, and Rh K-edge XAFS studies showed formation of Rh nanoparticles from [(CAAC)Rh(COD)Cl], in contrast to a previous report of [(CAAC)Rh(COD)Cl] functioning as a homogeneous catalyst for arene hydrogenation. We determined that the site-selective arene hydrogenation catalyzed by this system is under steric control, as shown by detailed competition experiments with derivatives of ethers, amides, and esters bearing different aromatic rings of varying electronic and steric influence. This work illustrates the potential of CAAC ligands in the formation and stabilization of a colloidal dispersion of stable nanoparticle catalysts.
- Tran, Ba L.,Fulton, John L.,Linehan, John C.,Lercher, Johannes A.,Bullock, R. Morris
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p. 8441 - 8449
(2018/08/17)
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- A carbonylation reaction of carbon monoxide in the method of preparing amide
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The invention belongs to the technical field of synthesis of amides, discloses a process for the carbonylation of carbon monoxide in the method of preparing amide, the method is to cheap and easy to obtain the halogenated aromatic hydrocarbon and organic amine compounds as the substrate of reaction, to carbon monoxide as carbonyl source, under light-struck, halogenated aromatic hydrocarbons are cracked to produce free radical, by free-radical addition process to obtain the amide compound. Compared with the traditional carbonylation reaction, the carbon monoxide pressure is extremely low, can react to the atmospheric pressure. This process does not need to rely on any metal catalyst of the booster, mild reaction conditions, environmental protection, with a shorter synthetic route and high utilization efficiency of the atoms, the reaction system with higher substrate tolerance, green sustainable light source as the driving force, the atom economy is high, application prospect.
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Paragraph 0024; 0025; 0026; 0027-0032; 0077; 0078; 0145
(2018/07/30)
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- Nickel (II)-Catalyzed efficient aminocarbonylation of unreactive alkanes with formanilides—Exploiting the deformylation behavior of imides
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Challenging functionalization of C(sp3)-H has recently attracted much attention of organic chemists. In this paper, we developed a Ni(acac)2-catalyzed activation of unreactive alkanes with formanilides in the presence of carbon monoxide to furnish moderate to excellent yields of amides. This is the first example of aminocarbonylation of inert alkanes using nickel-based catalyst, and formanilides is disclosed to be an interesting amine source owing to the peculiar deformylation nature of imide intermediates.
- Han, Zhang,Chaowei, Dai,Lice, Liu,Hongfei, Ma,Hongzhong, Bu,Yufeng, Li
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p. 3712 - 3718
(2018/05/29)
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- Method used for preparing amides via catalysis of halogenated aromatic hydrocarbons, amines, and carbon monoxide carbonylation with precious metal
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The invention discloses a method used for preparing amides via catalysis of halogenated aromatic hydrocarbons, amines, and carbon monoxide carbonylation with precious metal. According to the method, palladium acetate and triphenyl phosphine are taken as catalysts; a super strong alkali system is composed of potassium hydroxide and dimethyl sulphoxide, p-benzoquinone is taken as an oxidizing agent, carbon monoxide gas is taken as a carbonyl source, aniline is taken as a solvent, iodobenzene is taken as a substrate, carbonylation of iodobenzene into azophenyl benzamide at room temperature under normal pressure is realized. The method is high in conversion rate; reaction conditions are mild; less environment pollution is caused; the method is beneficial for large scale industrialized production, and promising application prospect and economic benefits are achieved.
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Paragraph 0019; 0051; 0060
(2017/10/07)
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- Combining Eosin y with Selectfluor: A Regioselective Brominating System for Para-Bromination of Aniline Derivatives
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A mild, metal-free, and absolutely para-selective bromination of aniline derivatives has been developed in excellent yields, wherein the organic dye Eosin Y is employed as the bromine source in company with Selectfluor. Neither air nor moisture sensitive, this facile reaction proceeds smoothly at room temperature and completes within a short time. Mechanistic studies indicate a radical pathway; therefore, the existence of an in situ generated brominating reagent, "Selectbrom", is postulated, which may reasonably account for the unique regioselectivity for the para-bromination of N-acyl- as well as N-sulfonylanilines.
- Huang, Binbin,Zhao, Yating,Yang, Chao,Gao, Yuan,Xia, Wujiong
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supporting information
p. 3799 - 3802
(2017/07/26)
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- Hypervalent Iodine-Mediated Oxidative Rearrangement of N-H Ketimines: An Umpolung Approach to Amides
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An umpolung approach to amides via hypervalent iodine-mediated oxidative rearrangement of N-H ketimines under mild reaction conditions is described. This strategy provides target amides with excellent selectivity in good yields. In addition, preliminary m
- Zhao, Zhenguang,Peng, Zhiyuan,Zhao, Yongli,Liu, Hao,Li, Chongnan,Zhao, Junfeng
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p. 11848 - 11853
(2017/11/28)
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- A Cross-Coupling Approach to Amide Bond Formation from Esters
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A palladium-catalyzed cross-coupling between aryl esters and anilines is reported, enabling access to diverse amides. The reaction takes place via activation of the C-O bond by oxidative addition with a Pd-NHC complex, which enables the use of relatively non-nucleophilic anilines that otherwise require stoichiometric activation with strong bases in order to react. High yields of aromatic, aliphatic, and heterocyclic products are obtained. A range of activated esters are evaluated in the presence and absence of catalyst, demonstrating that the catalytic methodology substantially increases the types of electrophiles that can be utilized for amide bond formation in the absence of harsh bases.
- Ben Halima, Taoufik,Vandavasi, Jaya Kishore,Shkoor, Mohanad,Newman, Stephen G.
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p. 2176 - 2180
(2017/08/09)
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- Nickel/Photoredox-Catalyzed Amidation via Alkylsilicates and Isocyanates
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A nickel/photoredox, dual-catalyzed amidation reaction between alkylsilicate reagents and alkyl/aryl isocyanates is reported. In contrast to the previously reported reductive coupling process, this protocol is characterized by mild reaction conditions and the absence of a stoichiometric reductant. A mechanistic hypothesis involving a nickel-isocyanate adduct is proposed based on literature precedent and further validation by experimental results.
- Zheng, Shuai,Primer, David N.,Molander, Gary A.
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p. 7957 - 7961
(2017/11/10)
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- Nickel-catalyzed transamidation of aliphatic amide derivatives
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Transamidation, or the conversion of one amide to another, is a long-standing challenge in organic synthesis. Although notable progress has been made in the transamidation of primary amides, the transamidation of secondary amides has remained underdeveloped, especially when considering aliphatic substrates. Herein, we report a two-step approach to achieve the transamidation of secondary aliphatic amides, which relies on non-precious metal catalysis. The method involves initial Boc-functionalization of secondary amide substrates to weaken the amide C-N bond. Subsequent treatment with a nickel catalyst, in the presence of an appropriate amine coupling partner, then delivers the net transamidated products. The transformation proceeds in synthetically useful yields across a range of substrates. A series of competition experiments delineate selectivity patterns that should influence future synthetic design. Moreover, the transamidation of Boc-activated secondary amide derivatives bearing epimerizable stereocenters underscores the mildness and synthetic utility of this methodology. This study provides the most general solution to the classic problem of secondary amide transamidation reported to date.
- Dander, Jacob E.,Baker, Emma L.,Garg, Neil K.
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p. 6433 - 6438
(2017/08/29)
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- Metal-free radical oxidative alkoxycarbonylation and imidation of alkanes
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A metal-free radical oxidative carbonylation of alkanes is demonstrated, yielding esters and imides by means of di-tert-butylperoxide as an oxidant. Various alkanes, alcohols and amides were compatible in this system generating the desired carbonyl products in up to 86% yields. We proposed a plausible radical cross-coupling process based on the preliminary mechanistic studies.
- Lu, Lijun,Cheng, Danyang,Zhan, Yuanfeng,Shi, Renyi,Chiang, Chien-Wei,Lei, Aiwen
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supporting information
p. 6852 - 6855
(2017/07/10)
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- N - substituted benzyl amino phosphine pliers link ruthenium double phosphine compound and its preparation method and application
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The invention relates to an N-substituted benzylaminophosphonic pincer-type cyclo-ruthenium diphosphonic compound, and a preparation method and an application for the N-substituted benzylaminophosphonic pincer-type cyclo-ruthenium diphosphonic compound. The preparation method comprises the following steps of adding amine phosphine, substituted benzyl alcohol, diphosphine ligand, RuC12(PPh3)3 and alkali into organic solvent; heating the mixture under the protection of N2 gas; filtering and recrystallizing the mixture so as to obtain the N-substituted benzylaminophosphonic pincer-type cyclo-ruthenium diphosphonic compound after the reaction is completed, wherein the process of synthesizing the N-substituted benzylaminophosphonic pincer-type cyclo-ruthenium diphosphonic compound is eliminated, so that the reaction operation is simple, and the preparation is easy. According to the preparation method, the N-substituted benzylaminophosphonic pincer-type cyclo-ruthenium diphosphonic compound is taken as a metal catalyst for catalytically synthesizing and preparing amide compounds. The preparation method has the advantages of low price and wide range of reaction substrates, mild condition, high efficiency and practicability, and has important application values.
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Paragraph 0060; 0061
(2017/10/07)
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