- Cation Radical-Accelerated Nucleophilic Aromatic Substitution for Amination of Alkoxyarenes
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Nucleophilic aromatic substitution (SNAr) is a common method for arene functionalization; however, reactions of this type are typically limited to electron-deficient aromatic halides. Herein, we describe a mild, metal-free, cation-radical accelerated nucleophilic aromatic substitution (CRA-SNAr) using a potent, highly oxidizing acridinium photoredox catalyst. Selective substitution of arene C-O bonds on a wide array of aryl ether substrates was shown with a variety of primary amine nucleophiles. Mechanistic evidence is also presented that supports the proposed CRA-SNAr pathway.
- Venditto, Nicholas J.,Nicewicz, David A.
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- Photocatalytic one-pot multidirectional N-alkylation over Pt/D-TiO2/Ti3C2: Ti3C2-based short-range directional charge transmission
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Visible-light-induced one-pot, multistep, and chemoselectivity adjustable reactions highlight the economical, sustainable, and green process. Herein, we report Pt nanoparticles dispersed on S and N co-doped titanium dioxide/titanium carbide (MXene) (3%Pt/
- Jiang, Heyan,Sheng, Meilin,Li, Yue,Kong, Shuzhen,Bian, Fengxia
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- A Fe single atom on N,S-doped carbon catalyst for performing N-alkylation of aromatic amines under solvent-free conditions
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A green and gram-scale strategy has been developed for the synthesis of Fe single atom/N,S-doped carbon catalyst (Fe20-SA@NSC) via the pyrolysis of polyaniline (PAN)-modified Fe,S-doped ZIFs, in which the synthesis of ZIFs can be accomplished in water at room temperature. The as-prepared catalyst exhibits superior activity in the N-alkylation of amines with alcohols via a borrowing strategy under solvent-free conditions (TOF up to 13.9 h-1). Based on the HAADF-STEM and XAFS results, Fe in this material is dispersed as the single-atom Fe1-N4S1 site. According to the experimental and theoretical calculation results, the Fe1-N4S1 site displays a better borrowing hydrogen ability than other Fe sites owing to its higher electron density. In addition, this catalyst has excellent stability and recyclability, and no obvious loss in activity is observed after 7 runs.
- Lin, Yamei,Lu, Guo-Ping,Shan, Hongbin,Wang, Pengcheng,Zhang, Kai,Zhong, Qin,Zhou, Baojing
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supporting information
p. 25128 - 25135
(2021/11/26)
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- Synthesis of NHC-Iridium(III) Complexes Based on N-Iminoimidazolium Ylides and Their Use for the Amine Alkylation by Borrowing Hydrogen Catalysis
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Anionic NHC ligands recently developed in our group, derived from N-iminoimidazolium ylides, were used to synthesize NHC-iridium(III) complexes. Their catalytic activities were evaluated in the amine alkylation of anilines using borrowing hydrogen catalysis. The high-yielding synthesis of a small library of complexes allowed a rapid screening of the ideal steric bulk of the NHC unit and basicity of the anionic tether for the investigated model reaction. A bulky aromatic N group on the imidazolidene moiety is required to achieve high catalytic activity, and the latter is proportional to the basicity of the anionic group. A selected substrate scope of the reaction was performed, providing fair to excellent yields of the desired alkylated anilines.
- Guérin, Vincent,Legault, Claude Y.
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supporting information
p. 408 - 417
(2021/02/01)
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- Designed pincer ligand supported Co(ii)-based catalysts for dehydrogenative activation of alcohols: Studies onN-alkylation of amines, α-alkylation of ketones and synthesis of quinolines
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Base-metal catalystsCo1,Co2andCo3were synthesized from designed pincer ligandsL1,L2andL3having NNN donor atoms respectively.Co1,Co2andCo3were characterized by IR, UV-Vis. and ESI-MS spectroscopic studies. Single crystal X-ray diffraction studies were investigated to authenticate the molecular structures ofCo1andCo3. CatalystsCo1,Co2andCo3were utilized to study the dehydrogenative activation of alcohols forN-alkylation of amines, α-alkylation of ketones and synthesis of quinolines. Under optimized reaction conditions, a broad range of substrates including alcohols, anilines and ketones were exploited. A series of control experiments forN-alkylation of amines, α-alkylation of ketones and synthesis of quinolines were examined to understand the reaction pathway. ESI-MS spectral studies were investigated to characterize cobalt-alkoxide and cobalt-hydride intermediates. Reduction of styrene by evolved hydrogen gas during the reaction was investigated to authenticate the dehydrogenative nature of the catalysts. Probable reaction pathways were proposed forN-alkylation of amines, α-alkylation of ketones and synthesis of quinolines on the basis of control experiments and detection of reaction intermediates.
- Singh, Anshu,Maji, Ankur,Joshi, Mayank,Choudhury, Angshuman R.,Ghosh, Kaushik
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p. 8567 - 8587
(2021/06/30)
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- Mimicking transition metals in borrowing hydrogen from alcohols
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Borrowing hydrogen from alcohols, storing it on a catalyst and subsequent transfer of the hydrogen from the catalyst to anin situgenerated imine is the hallmark of a transition metal mediated catalyticN-alkylation of amines. However, such a borrowing hydrogen mechanism with a transition metal free catalytic system which stores hydrogen molecules in the catalyst backbone is yet to be established. Herein, we demonstrate that a phenalenyl ligand can imitate the role of transition metals in storing and transferring hydrogen molecules leading to borrowing hydrogen mediated alkylation of anilines by alcohols including a wide range of substrate scope. A close inspection of the mechanistic pathway by characterizing several intermediates through various spectroscopic techniques, deuterium labelling experiments, and DFT study concluded that the phenalenyl radical based backbone sequentially adds H+, H˙ and an electron through a dearomatization process which are subsequently used as reducing equivalents to the C-N double bond in a catalytic fashion.
- Banik, Ananya,Ahmed, Jasimuddin,Sil, Swagata,Mandal, Swadhin K.
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p. 8353 - 8361
(2021/07/02)
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- Trimethyl Borate-Catalyzed, Solvent-Free Reductive Amination
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Solvent-free reductive amination of aldehydes and ketones with aliphatic and aromatic amines in high-to-excellent yields has been achieved with sub-stoichiometric trimethyl borate as promoter and ammonia borane as reductant.
- Ramachandran, P. Veeraraghavan,Choudhary, Shivani,Singh, Aman
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p. 4274 - 4280
(2021/03/09)
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- Transfer Hydrogenation of Ketones and Imines with Methanol under Base-Free Conditions Catalyzed by an Anionic Metal-Ligand Bifunctional Iridium Catalyst
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An anionic iridium complex [Cp*Ir(2,2′-bpyO)(OH)][Na] was found to be a general and highly efficient catalyst for transfer hydrogenation of ketones and imines with methanol under base-free conditions. Readily reducible or labile substituents, such as nitro, cyano, and ester groups, were tolerated under present reaction conditions. Notably, this study exhibits the unique potential of anionic metal-ligand bifunctional iridium catalysts for transfer hydrogenation with methanol as a hydrogen source.
- Han, Xingyou,Li, Feng,Liu, Peng,Wang, Rongzhou,Xu, Jing
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p. 2242 - 2249
(2020/03/13)
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- Efficient photocatalytic one-pot hydrogenation and N-alkylation of nitrobenzenes/benzonitriles with alcohols over Pd/MOFs: Effect of the crystal morphology & “quasi-MOF” structure
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One-pot multi-step reactions over visible-light induced catalysis feature the sustainable green process. Here, ligand structure change and 2-MI coordinated modulation were adapted to adjust the crystal size, morphology and crystalline structure of Fe-MOFs; double solvent impregnation was employed for the Pd loading; “quasi-MOF” materials with retained morphology were formed with calcination under N2. Above modified materials were employed as multifunctional photocatalysts for highly efficient one-pot hydrogenation and N-alkylation of nitrobenzenes or benzonitriles with alcohols after in situ Pd photoreduction. Photocatalytic performance was evidently affected by the Fe-MOFs crystal size, morphology, crystalline structure alteration and “quasi-MOF” construction. One-pot hydrogenation and N-alkylation of benzonitriles with alcohols was achieved with excellent catalytic performance firstly in heteroegeneous catalysis. Reaction mechanism was proposed with the assistance of in situ DRIFTS.
- Bian, Fengxia,Cheng, Hongmei,Jiang, Heyan,Liu, Xingyan,Long, Xingyu,Yang, Chaofen
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p. 121 - 131
(2020/06/23)
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- Pyridine mediated transition-metal-free direct alkylation of anilines using alcohols: via borrowing hydrogen conditions
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Herein, we report pyridine and other similar azaaromatics as efficient biomimetic hydrogen shuttles for a transition-metal-free direct N-alkylation of aryl and heteroaryl amines using a variety of benzylic and straight chain alcohols. Mechanistic studies including deuterium labeling and the isolation of dihydro-intermediates of the benzannulated pyridine confirmed the role of pyridine and a borrowing hydrogen process operating in these reactions. In addition, we have extended this methodology for the development of dehydrogenative synthesis of quinolines and indoles, as well as the transfer hydrogenation of ketones. This journal is
- Pothikumar, Rajagopal,Bhat, Venugopal T,Namitharan, Kayambu
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supporting information
p. 13607 - 13610
(2020/11/17)
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- Bidentate geometry-constrained iminopyridyl nickel-catalyzed synthesis of amines or imines via borrowing hydrogen or dehydrogenative condensation
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The efficient Ni-catalyzed N-alkylation of various anilines with alcohols via borrowing hydrogen is reported using a bidentate geometry-constrained iminopyridyl nickel complex as the catalyst. Substituted benzylic alcohols and short/long chain aliphatic alcohols could be applied as the alkylation sources to couple with aromatic and heteroaromatic amines to give a diverse set of N-alkylation outcomes in moderate to excellent yields. The nickel catalytic system was also suitable for aliphatic amines, selectively delivering the corresponding imines via an acceptorless dehydrogenative condensation strategy.
- Jiang, Yong,Hu, Miao,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Hu, Xinquan,Jin, Liqun
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supporting information
(2020/11/27)
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- Thiazoline-Iridium (III) Complexes and Immobilized Nanomaterials as Selective Catalysts in N-Alkylation of Amines with Alcohols
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In this research, a new series of thiazoline-iridium (III) complexes (4–7) derived from cysteine were prepared and fully characterized by conventional methods. The molecular structure of complex 5 was also determined by single-crystal X-ray diffraction. These complexes were evaluated as catalysts for hydrogen-borrowing reactions of amines with alcohols. In particular, complex 5 showed the best activity as catalyst. Various amines have been alkylated with alcohols affording moderate to good yield (33–99%). Moreover, the immobilized nanomaterials (M1,2) were fabricated by sonication process from the best catalyst 5 with the multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO), respectively, and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) spectroscopy, and inductively coupled plasma-mass spectrometry (ICP-MS). The M1,2 nanomaterials were also tested as catalysts in model catalytic reaction for N-alkylation. The M1 nanomaterial showed significantly higher activity than the M2 nanomaterial. The M1 catalyst was recovered by filtration and reused for four catalytic cycles with high conversion (99%, 97%, 96%, and 86%).
- Denizalt?, Serpil,Dayan, Serkan,Günnaz, Salih,?ahin, Ertan
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- Direct electrochemical reductive amination between aldehydes and amines with a H/D-donor solvent
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A novel electrochemical synthesis protocol has been achieved for reductive amination between aldehydes and amines in undivided cells at room temperature. Under metal-free and external-reductant-free electrolysis conditions, various important secondary amine products are obtained in moderate-to-high yields. Deuterium-labeling experiments have demonstrated that low-toxicity DMSO acts both as a solvent and a H-donor in the reaction. On this basis, various deuterium-labeled products with good-to-excellent D-incorporation have been synthesized by using DMSO-d6 as a solvent. Furthermore, a molecule with GR-antagonistic activity has been synthesized through further sulfonylation.
- Chen, Lu,Hong, Huanliang,Hu, Jinhui,Huang, Yubing,Li, Yibiao,Liang, Gen,Pu, Suyun,Zhu, Zhongzhi,Zou, Zirong
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supporting information
p. 5832 - 5837
(2020/11/03)
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- Dialkylterphenyl Phosphine-Based Palladium Precatalysts for Efficient Aryl Amination of N-Nucleophiles
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A series of 2-aminobiphenyl palladacycles supported by dialkylterphenyl phosphines, PR2Ar′ (R=Me, Et, iPr, Cyp (cyclopentyl), Ar′=ArDipp2, ArXyl2f, Dipp (2,6-C6H3-(2,6-C6H3-(CHMe2)2)2), Xyl=xylyl) have been prepared and structurally characterized. Neutral palladacycles were obtained with less bulky terphenyl phosphines (i.e., Me and Et substituents) whereas the largest phosphines provided cationic palladacycles in which the phosphines adopted a bidentate hemilabile k1-P,η1-Carene coordination mode. The influence of the ligand structure on the catalytic performance of these Pd precatalysts was evaluated in aryl amination reactions. Cationic complexes bearing the phosphines PiPr2ArXyl2 and PCyp2ArXyl2 were the most active of the series. These precatalysts have demonstrated a high versatility and efficiency in the coupling of a variety of nitrogen nucleophiles, including secondary amines, alkyl amines, anilines, and indoles, with electronically deactivated and ortho-substituted aryl chlorides at low catalyst loadings (0.25–0.75 mol % Pd) and without excess ligand.
- Rama, Raquel J.,Maya, Celia,Nicasio, M. Carmen
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supporting information
p. 1064 - 1073
(2020/01/25)
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- A nanoscale iron catalyst for heterogeneous direct: N - And C -alkylations of anilines and ketones using alcohols under hydrogen autotransfer conditions
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Here, we report a commercially available nanoscale Fe catalyst for heterogeneous direct N- and C-alkylation reactions of anilines and methyl ketones with alcohols. A hydrogen autotransfer mechanism has been found to operate in these reactions by deuterium labelling studies. In addition, dehydrogenative quinoline synthesis has been demonstrated from amino benzyl alcohols and acetophenones.
- Nallagangula, Madhu,Sujatha, Chandragiri,Bhat, Venugopal T.,Namitharan, Kayambu
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supporting information
p. 8490 - 8493
(2019/07/22)
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- Para-Selective C-H Olefination of Aniline Derivatives via Pd/S,O-Ligand Catalysis
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Herein we report a highly para-selective C-H olefination of aniline derivatives by a Pd/S,O-ligand-based catalyst. The reaction proceeds under mild reaction conditions with high efficiency and broad substrate scope, including mono-, di-, and trisubstituted tertiary, secondary, and primary anilines. The S,O-ligand is responsible for the dramatic improvements in substrate scope and the high para-selectivity observed. This methodology is operationally simple, scalable, and can be performed under aerobic conditions.
- Naksomboon, Kananat,Poater, Jordi,Bickelhaupt, F. Matthias,Fernández-Ibá?ez, M. ángeles
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supporting information
p. 6719 - 6725
(2019/05/06)
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- Oxalic amide ligands, and uses thereof in copper-catalyzed coupling reaction of aryl halides
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The present invention provides oxalic amide ligands and uses thereof in copper-catalyzed coupling reaction of aryl halides. Specifically, the present invention provides a use of a compound represented by formula I, wherein definitions of each group are described in the specification. The compound represented by formula I can be used as a ligand in copper-catalyzed coupling reaction of aryl halides for the formation of C—N, C—O and C—S bonds.
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Page/Page column 77-78
(2020/01/09)
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- N-Alkylation of Aniline and Its Derivatives by Alcohols in the Presence of Copper Compounds
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N-Alkyl- and N,N-dialkyl-substituted anilines were obtained in the reaction of aniline and its derivatives with primary and secondary alcohols in the presence of catalysts CuCl2·2H2O, CuBr2 and halomethanes as promoters.
- Bayguzina,Musina, Ch. F.,Khusnutdinov
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p. 1652 - 1659
(2019/02/12)
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- Grouping Effect of Single Nickel?N4 Sites in Nitrogen-Doped Carbon Boosts Hydrogen Transfer Coupling of Alcohols and Amines
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As a new type of heterogeneous catalyst with “homogeneous-like” activity, single-site transition-metal materials are usually treated as integrated but separate active centers. A novel grouping effect is reported for single Ni?N4 sites in nitrogen-doped carbon (Ni/NC), where an effective ligand-stabilized polycondensation method endows Ni/NC nanocatalysts with a high content of single-site Ni up to 9.5 wt %. The enhanced electron density at each single Ni?N4 site promotes a highly efficient hydrogen transfer, which is exemplified by the coupling of benzyl alcohol and aniline into N-benzylaniline with a turnover frequency (TOF) value of 7.0 molN-benzylaniline molmetal?1 h?1; this TOF outpaces that of reported stable non-noble-metal-based catalysts by a factor of 2.
- Su, Hui,Gao, Peng,Wang, Meng-Ying,Zhai, Guang-Yao,Zhang, Jun-Jun,Zhao, Tian-Jian,Su, Juan,Antonietti, Markus,Li, Xin-Hao,Chen, Jie-Sheng
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supporting information
p. 15194 - 15198
(2018/10/31)
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- One-pot reductive amination of aldehydes with nitroarenes using formic acid as the hydrogen donor and mesoporous graphitic carbon nitride supported AgPd alloy nanoparticles as the heterogeneous catalyst
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Herein, we report a one-pot protocol for the synthesis of secondary amines via a tandem reductive amination of aldehydes with nitroaromatics utilizing mesoporous graphitic carbon nitride (mpg-C3N4) supported AgPd alloy nanoparticles (mpg-C3N4/AgPd) as the catalyst, FA as the hydrogen donor and water as the sole solvent, which is a protocol in harmony with the green chemistry rules. In the present one-pot catalytic reductive amination protocol, a variety of secondary amines (11 examples) were yielded by using nitroarenes as a nitrogen source and benzaldehyde in the presence of the mpg-C3N4/AgPd nanocatalyst, which is the first example in the literature. Monodisperse AgPd alloy NPs (2.5 ± 0.5 nm) were synthesized by using our established protocol via the co-reduction of silver(i) acetate and palladium(ii) acetylacetonate in the presence of oleylamine and oleic acid as surfactants in a hot organic solvent. The as-prepared AgPd alloy nanoparticles were then deposited on mpg-C3N4via a liquid phase self-assembly method. After the structural characterization of the mpg-C3N4/AgPd nanocatalyst using TEM, PXRD, BET and ICP-MS analyses, they were directly tested in one-pot direct reductive amination reactions in which they showed superior activity. The applicability of the present one-pot reductive amination strategy was demonstrated over a variety of aldehydes and nitroarenes (11 examples). Moreover, the mpg-C3N4/AgPd catalyst was a reusable catalyst in the reductive amination reactions providing 99% yield even after five consecutive runs.
- Ergen, Seda,Ni?anci, Bilal,Metin, ?nder
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p. 10000 - 10006
(2018/06/18)
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- BINAP-copper supported by hydrotalcite as an efficient catalyst for the borrowing hydrogen reaction and dehydrogenation cyclization under water or solvent-free conditions
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A BINAP-Cu system supported by hydrotalcite has been developed and proved to be a highly efficient catalyst for the atom-efficient and green borrowing hydrogen reaction and dehydrogenative cyclization. This BINAP-Cu complex supported by hydrotalcite is highly air-stable and can be recycled at least five times under solvent-free conditions. Notably, 1-benzyl-2-aryl-1H-benzo[d]imidazole derivatives could be synthesized from alcohols in only one step with water as the solvent for the first time. This provided a much greener and efficient catalytic method towards the synthesis of functionalized amines, ketones and 1-benzyl-2-aryl-1H-benzo[d]imidazole derivatives with high yields under water or solvent-free conditions.
- Xu, Zhaojun,Yu, Xiaoli,Sang, Xinxin,Wang, Dawei
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supporting information
p. 2571 - 2577
(2018/06/11)
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- Direct Aryl C?H Amination with Primary Amines Using Organic Photoredox Catalysis
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The direct catalytic C?H amination of arenes is a powerful synthetic strategy with useful applications in pharmaceuticals, agrochemicals, and materials chemistry. Despite the advances in catalytic C?H functionalization, the use of aliphatic amine coupling partners is limited. Described herein is the construction of C?N bonds, using primary amines, by direct C?H functionalization with an acridinium photoredox catalyst under an aerobic atmosphere. A wide variety of primary amines, including amino acids and more complex amines are competent coupling partners. Various electron-rich aromatics and heteroaromatics are useful scaffolds in this reaction, as are complex, biologically active arenes. We also describe the ability to functionalize arenes that are not oxidized by an acridinium catalyst, such as benzene and toluene, thus supporting a reactive amine cation radical intermediate.
- Margrey, Kaila A.,Levens, Alison,Nicewicz, David A.
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supporting information
p. 15644 - 15648
(2017/11/20)
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- Base-assisted, copper-catalyzed N-arylation of (benz)imidazoles and amines with diarylborinic acids
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N-Arylation of (benz)imidazoles and amines with diarylborinic acids as cost-effective aryl source has been efficiently effected via Cu(OAc)2-catalyzed Chan-Lam coupling in assistance of tetramethylethylenediamine (TMEDA) in methanol and pyridine (Py) in dichloromethane, respectively, in air at room temperature. The diarylborinic acids could be well accommodated by the Chan-Lam coupling oxidative conditions containing a proper combination of bases and solvents. The steric hindrance appeared to affect the copper-catalyzed N-arylation using the high-order arylboron reagent more significantly than the electronic factors, especially for low reactive anilines and aliphatic amines.
- Guan, Changwei,Feng, Yuanyuan,Zou, Gang,Tang, Jie
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p. 6906 - 6913
(2017/11/03)
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- Tunable Ligand Effects on Ruthenium Catalyst Activity for Selectively Preparing Imines or Amides by Dehydrogenative Coupling Reactions of Alcohols and Amines
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Selective dehydrogenative synthesis of imines from a variety of alcohols and amines was developed by using the ruthenium complex [RuCl2(dppea)2] (6 a: dppea=2-diphenylphosphino-ethylamine) in the presence of catalytic amounts of Zn(OCOCF3)2 and KOtBu, whereas the selective dehydrogenative formation of amides from the same sources was achieved by using another ruthenium complex, [RuCl2{(S)-dppmp}2] [6 d: (S)-dppmp=(S)-2-((diphenylphosphenyl)methyl)pyrrolidine], in the presence of catalytic amounts of Zn(OCOCF3)2 and potassium bis(trimethylsilyl)amide (KHMDS). Our previously reported ruthenium complex, [Ru(OCOCF3)2(dppea)2] (8 a), was the catalyst precursor for the imine synthesis, whereas [Ru(OCOCF3)2{(S)-dppmp}2] (8 d), which was derived from the treatment of 6 d with Zn(OCOCF3)2 and characterized by single-crystal X-ray analysis, was the pre-catalyst for the amide formation. Control experiments revealed that the zinc salt functioned as a reagent for replacing chloride anions with trifluoroacetate anions. Plausible mechanisms for both selective dehydrogenative coupling reactions are proposed based on a time-course study, Hammett plot, and deuterium-labeling experiments.
- Higuchi, Takafumi,Tagawa, Risa,Iimuro, Atsuhiro,Akiyama, Shoko,Nagae, Haruki,Mashima, Kazushi
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p. 12795 - 12804
(2017/09/06)
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- AgPd Nanoparticles Deposited on WO2.72 Nanorods as an Efficient Catalyst for One-Pot Conversion of Nitrophenol/Nitroacetophenone into Benzoxazole/Quinazoline
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We report a seed-mediated growth of 2.3 nm AgPd nanoparticles (NPs) in the presence of 40 × 5 nm WO2.72 nanorods (NRs) for the synthesis of AgPd/WO2.72 composites. The strong interactions between AgPd NPs and WO2.72 NRs make the composites, especially the Ag48Pd52/WO2.72, catalytically active for dehydrogenation of formic acid (TOF = 1718 h-1 and Ea = 31 kJ/mol) and one-pot reactions of formic acid, 2-nitrophenol, and aldehydes into benzoxazoles in near quantitative yields under mild conditions. The catalysis can also be extended to the one-pot reactions of ammonium formate, 2-nitroacetophenone, and aldehyde for high yield syntheses of quinazolines. Our studies demonstrate a new catalyst design to achieve a green chemistry approach to one-pot reactions for the syntheses of benzoxazoles and quinazolines.
- Yu, Chao,Guo, Xuefeng,Xi, Zheng,Muzzio, Michelle,Yin, Zhouyang,Shen, Bo,Li, Junrui,Seto, Christopher T.,Sun, Shouheng
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supporting information
p. 5712 - 5715
(2017/05/04)
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- General Reductive Amination of Aldehydes and Ketones with Amines and Nitroaromatics under H2 by Recyclable Iridium Catalysts
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Heterogeneous iridium catalysts were prepared and applied for the reductive amination of aldehydes and ketones with nitroaromatics and amines using H2. The iridium catalysts were prepared by pyrolysis of ionic liquid 1-methyl-3-cyanomethylimidazoulium chloride ([MCNI]Cl) with iridium chloride (IrCl3) in activated carbons. Iridium particles were well dispersed and stable in the N-doped carbon materials from [MCNI]Cl with activated carbon. The Ir@NC(600-2h) catalyst was found to be highly active and selective for the reductive amination of aldehydes and ketones using H2 and a variety of nitrobenzenes and amines were selectively converted into the corresponding secondary and tertiary amines. The Ir@NC(600-2h) catalyst can be reusable several times without evident deactivation.
- Sui, Dejun,Mao, Fei,Fan, Haipeng,Qi, Zhengliang,Huang, Jun
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supporting information
p. 1371 - 137
(2017/10/05)
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- An Efficient Homogenized Ruthenium(II) Pincer Complex for N-Monoalkylation of Amines with Alcohols
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An ionic 2,6-bis(imidazo[1,2-α]pyridin-2-yl)pyridine-based N^N^N pincer ruthenium(II) complex exhibited high efficiency in the C–N bond formation between amines and alcohols by the “borrowing hydrogen” (BH) or “hydrogen autotransfer” (HA) concept. The synthetic protocol selectively generated monoalkylated amines without formation of tertiary amines during the reaction. The unique selectivity enabled the formation of symmetrically and asymmetrically substituted diamines. This methodology features several advantages including a low catalyst loading (as low as 0.5 mol-%), a short reaction time (as short as 2 h), and excellent N-monoalkylation selectivity.
- Yang, Fa-Liu,Wang, Ying-Hui,Ni, Yong-Feng,Gao, Xiang,Song, Bing,Zhu, Xinju,Hao, Xin-Qi
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p. 3481 - 3486
(2017/07/04)
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- Cyclometalated palladium pre-catalyst for N-alkylation of amines using alcohols and regioselective alkylation of sulfanilamide using aryl alcohols
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Simple pyrazole based palladacycle-phosphine with a high turnover has been developed and applied for the N-alkylation of amines and sulfanilamide using alcohols as substrates by hydrogen borrowing strategy. N-alkylation of primary and secondary amines resulted in high isolated yields at 100–130 °C, under solvent free conditions. More challenging secondary aliphatic as well as aromatic alcohols were also successfully utilized as alkylating agents under similar reaction conditions. The turn over number reached up to 43000 for N-benzylation of aniline using benzyl alcohol. Notably, regioselective N-alkylation of 2-aminobenzothiazole and 4-aminobenzenesulfonamide to the corresponding 2-N-(alkylamino)azoles and 4-amino-(N-alkyl)benzenesulfonamides using alcohols as alkylating agents have been achieved using our new pre-catalyst-phosphine system.
- Mamidala, Ramesh,Mukundam, Vanga,Dhanunjayarao, Kunchala,Venkatasubbaiah, Krishnan
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supporting information
p. 2225 - 2233
(2017/03/24)
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- A by a process for preparing amine derivatives of green method (by machine translation)
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The invention discloses a by a process for preparing amine derivatives of green method, dumping with amine compound in a non-transition metal catalyst under solvent-free conditions and through the controllable high selection dehydration alkylation reaction different amine derivatives, a non-transition metal catalyst is a halogenated hydrocarbon, halogenated hydrocarbon in an amount of 1 - 50 μM %, under the catalysis of the mellow and amine in halogenated hydrocarbon can be directly performed by the amine derivative dehydration reaction, the reaction temperature is 100 - 180 °C, the reaction time is 12 - 48 hours, the by-product is water, the reaction needs to be carried out under the protection of inert gas, simple conditions, easy to operate, the by-product is water, the reaction selectivity is controllable, the target high selectivity. Requirements for reaction condition of relatively low, primary and secondary alcohol can be used for the alkylation reagent, is suitable for the dehydration of the primary and secondary amines single alkylation reaction, is also suitable for the dehydration of the double alkylation reaction of a primary amine, with wider scope, should also has certain research and industrial application prospect. (by machine translation)
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Paragraph 0060 - 0063
(2017/08/14)
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- An Efficient and Selective Nickel-Catalyzed Direct N-Alkylation of Anilines with Alcohols
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Herein, we developed an efficient and selective nickel-catalyzed monoalkylation of various primary alcohols with aryl and heteroaryl amines together with diols and amino alcohol derivatives. Notably, the catalytic protocol consisting of an earth-abundant and non-precious NiBr2/L1 system enables the transformations in the presence of hydroxyl, alkene, nitrile, and nitro functionalities. As a highlight, we have demonstrated the alkylation of diamine, intramolecular cyclization to N-heterocycles, and functionalization of complex vitamin E, an (±)-α-tocopherol derivative. Preliminary mechanistic studies revealed the participation of a benzylic C-H bond in the rate-determining step.
- Vellakkaran, Mari,Singh, Khushboo,Banerjee, Debasis
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p. 8152 - 8158
(2017/12/08)
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- Tunable Triazole-Phosphine-Copper Catalysts for the Synthesis of 2-Aryl-1H-benzo[d]imidazoles from Benzyl Alcohols and Diamines by Acceptorless Dehydrogenation and Borrowing Hydrogen Reactions
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Triazole-phosphine-copper complexes (TAP?Cu) have been synthesized and applied as tunable and efficient catalysts for the selective synthesis of fluoro-substituted 2-aryl-1H-benzo[d]imidazole and 1-benzyl-2-aryl-1H-benzo[d]imidazole derivatives from simple alcohols in only one step. TAP?Cu exhibited excellent and tunable catalytic activity for both dehydrogenation and borrowing hydrogen reactions with more than 80 examples being demonstrated for the first time. It was observed that the ligand played a critical role in catalyst activity. Mechanistic studies and deuterium labeling experiments indicated that the reactions proceeded by an initial and reversible alcohol dehydrogenation resulting in a copper hydride intermediate. This was also supported by the direct observation of a diagnostic copper hydride signal by solid-state infrared spectroscopy. The TAP?Cu-H complex showed absorptions at 912 cm?1 that could be assigned to copper?hydride stretches. Furthermore, the direct trapping of an intermediate bisimine was also successfully performed. (Figure presented.).
- Xu, Zhaojun,Wang, Duo-Sheng,Yu, Xiaoli,Yang, Yongchun,Wang, Dawei
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supporting information
p. 3332 - 3340
(2017/10/06)
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- Flexible Steric Bulky Bis(Imino)acenaphthene (BIAN)-Supported N-Heterocyclic Carbene Palladium Precatalysts: Catalytic Application in Buchwald-Hartwig Amination in Air
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To achieve efficient palladium-catalyzed cross-coupling reaction under mild reaction conditions with the flexible steric bulk strategy, a series of Pd-PEPPSI (PEPPSI: pyridine-enhanced precatalyst preparation, stabilization, and initiation) complexes C1-C6 were synthesized and characterized, in which unsymmetric flexible steric bulk was introduced on the N-aryl of ancenaphthyl skeleton. These well-defined palladium complexes were found to be excellent precatalysts for Buchwald-Hartwig amination of aryl chlorides with amines in air. The electronic effect of the Pd-PEPPSI complexes and the effect of ancillary pyridine ligands were evaluated, among which complex C3 exhibited the most efficiency. It was demonstrated that the cross-coupling products were obtained in excellent yields in the presence of 0.5-0.1 mol % palladium loading. A wide range of aryl- and heteroaryl chlorides as well as various amines were compatible. The oxidative addition of aryl chlorides is revealed to be the rate-determining step in the catalytic cycle. The catalytic activity can be enhanced by introducing electron-donating groups to the Pd-PEPPSI complexes. This type of Pd-PEPPSI precatalyst showed the most efficiency reported to date for the challenging C-N cross-coupling reactions requiring no anhydrous and inert atmosphere protections, suggesting flexible steric bulk as a promising catalyst design strategy.
- Lan, Xiao-Bing,Li, Yinwu,Li, Yan-Fang,Shen, Dong-Sheng,Ke, Zhuofeng,Liu, Feng-Shou
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p. 2914 - 2925
(2017/03/23)
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- Oxidative amination of benzylic alkanes with nitrobenzene derivatives as nitrogen sources
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The oxidative amination of inert C[sbnd]H bonds has the potential to fundamentally change chemistry but is severely limited by the low chemo- and regio-selectivity under oxidation conditions. Until now, no efficient methodology for the direct intermolecular amination of terminal sp3-C[sbnd]H bonds to N-alkyl amines has existed. Here, a new concept is proposed for the oxidative amination of the terminal sp3-C[sbnd]H bond in alkanes via the construction of a complex reaction system composed of a carbon-supported Co-Ni bimetallic catalyst, an alkane, nitrobenzene, tert-butyl hydroperoxide and hydrogen. This system allows the reduction of nitrobenzene to aniline and the further oxidative amination of the alkane. Nitrobenzene and toluene derivatives can be successfully transformed into the corresponding N-benzyl aniline derivatives with up to 95% isolated yields, and the reaction shows excellent functional group tolerance. This approach offers a new concept for catalyst design and may strongly promote the study of inert C[sbnd]H bond activation and the synthesis of functional N-containing compounds.
- Pang, Shaofeng,Shi, Feng
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supporting information
p. 5872 - 5876
(2016/12/07)
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- Cobalt-Catalyzed N-Alkylation of Amines with Alcohols
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A well-defined nonprecious metal cobalt(II) catalyst based on a pincer PNP ligand has been employed for the efficient N-alkylation of both aromatic and aliphatic amines with alcohols. A subtle change of reaction conditions (simply adding 4 ? molecular sieves) was observed to readily switch the resulting products (amines vs imines) with high chemoselectivity. A range of alcohols and amines including both aromatic and aliphatic substrates were efficiently converted to secondary amines in good-to-excellent yields when 2 mol % cobalt catalyst was used. Additional experiments indicate that a hydrogen-borrowing mechanism is responsible for the tandem acceptorless dehydrogenation/condensation/hydrogenation process.
- Zhang, Guoqi,Yin, Zhiwei,Zheng, Shengping
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supporting information
p. 300 - 303
(2016/02/03)
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- Selective catalytic Hofmann: N -alkylation of poor nucleophilic amines and amides with catalytic amounts of alkyl halides
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Using only catalytic amounts of alkyl halides in the reactions of poor nucleophilic amines/amides and alcohols led to a selective Hofmann N-alkylation reaction catalytic in alkyl halides, providing a practical and efficient method for the practical synthesis of mono- or di-alkylated amines/amides in high selectivities. This new method avoids the use of large amounts of bases, alkyl halides, and solvents, and generates water as the only byproduct. Preliminary mechanistic studies showed that alkyl halides are key intermediates/catalysts regeneratable in the reaction cycle.
- Xu, Qing,Xie, Huamei,Zhang, Er-Lei,Ma, Xiantao,Chen, Jianhui,Yu, Xiao-Chun,Li, Huan
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supporting information
p. 3940 - 3944
(2016/07/21)
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- Heterogeneous cobalt catalysts for reductive amination with H2: General synthesis of secondary and tertiary amines
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Heterogeneous Co@NC catalysts were prepared, characterized and applied for the reductive amination of aldehydes and ketones with H2 gas. The Co catalyst Co@NC (800-2 h) was found to be active and selective for the reductive amination of aldehydes and ketones using H2 gas. Thus, general synthesis of secondary and tertiary amines was developed by the Co-catalyzed reductive amination with H2 gas, and various secondary and tertiary amines can be obtained in high yields. Moreover, a practical synthesis of N-substituted isoindolinones was also presented by a one step process with the Co@NC (800-2 h) catalyst. The Co@NC (800-2 h) catalyst is reusable at least five times without evident loss of activity.
- Mao, Fei,Sui, Dejun,Qi, Zhengliang,Fan, Haipeng,Chen, Rizhi,Huang, Jun
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p. 94068 - 94073
(2016/10/22)
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- Copper-catalyzed radical reactions of 2-azido-N-arylacrylamides with 1-(trifluoromethyl)-1,2-benziodoxole and 1-azidyl-1,2-benziodoxole
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The reactions of 2-azido-N-arylacrylamides with trifluoromethyl radicals and azidyl radicals were investigated by using Togni's reagent and Zhdankin's reagent as the source of these radicals. Under the catalysis of CuI, Togni's reagent was firstly converted into the trifluoromethyl radical, which then reacted with 2-azido-N-arylacrylamides to afford the corresponding α-(arylaminocarbonyl)iminyl radicals. The cyclization of the iminyl radicals delivered quinoxalin-2(1H)-one products in moderate yields. A similar reaction took place between 2-azido-N-arylacrylamides and the azidyl radical. In the latter cases, the reaction produced 3-azidomethyl and 3-cyano-subsituted quinoxalin-2(1H)-ones. This study not only helps elucidate the factors influencing the cyclization of α-(arylaminocarbonyl)iminyl radicals, but also provides a new approach towards quinoxalin-2-ones.
- Yang, Tonghao,Zhu, Haizhen,Yu, Wei
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supporting information
p. 3376 - 3384
(2016/04/09)
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- Thiol activated prodrugs of sulfur dioxide (SO2) as MRSA inhibitors
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Drug resistant infections are becoming common worldwide and new strategies for drug development are necessary. Here, we report the synthesis and evaluation of 2,4-dinitrophenylsulfonamides, which are donors of sulfur dioxide (SO2), a reactive sulfur species, as methicillin-resistant Staphylococcus aureus (MRSA) inhibitors. N-(3-Methoxyphenyl)-2,4-dinitro-N-(prop-2-yn-1-yl)benzenesulfonamide (5e) was found to have excellent in vitro MRSA inhibitory potency. This compound is cell permeable and treatment of MRSA cells with 5e depleted intracellular thiols and enhanced oxidative species both results consistent with a mechanism involving thiol activation to produce SO2.
- Pardeshi, Kundansingh A.,Malwal, Satish R.,Banerjee, Ankita,Lahiri, Surobhi,Rangarajan, Radha,Chakrapani, Harinath
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p. 2694 - 2697
(2015/06/08)
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- C-N bond formation between alcohols and amines using an iron cyclopentadienone catalyst
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An iron-tetraphenylcyclopentadienone tricarbonyl complex is demonstrated to act as a precursor of a catalyst for the formation of C-N bonds through a "hydrogen-borrowing" reaction between amines and alcohols.
- Rawlings, Andrew J.,Diorazio, Louis J.,Wills, Martin
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supporting information
p. 1086 - 1089
(2015/03/14)
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- Tert-Butyl Hydroperoxide and Tetrabutylammonium Iodide-Promoted Free Radical Cyclization of α-Imino-N-arylamides and α-Azido-N-arylamides
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The oxidizing system of tert-butyl hydroperoxide (TBHP) and tetrabutylammonium iodide (TBAI) is capable of generating α-(arylaminocarbonyl)iminyl radicals from ethyl 2-(N-arylcarbamoyl)-2-iminoacetates. These iminyl radicals preferably undergo intramolecular ipso attack on the benzene ring to give azaspirocyclohexadienyl radicals, which are readily captured by molecular oxygen under an oxygen atmosphere to yield azaspirocyclohexadienones. In the absence of oxygen, the reaction affords quinoxalin-2-one products. This oxidizing system is also effective to convert α-aryl-α-azido-N-arylamides to the corresponding iminyl radicals under basic conditions (sodium tert-butoxide, t-BuONa), and the subsequent cyclization of these iminyl radicals results in the formation of azaspirocyclohexadienone products in high yields under an oxygen atmosphere. Plausible mechanisms are proposed to rationalize the experimental results, and factors influencing the reactions are discussed.
- Li, Dianjun,Yang, Tonghao,Su, Hailin,Yu, Wei
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supporting information
p. 2529 - 2539
(2015/08/18)
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- Selective Monoarylation of Primary Amines Using the Pd-PEPPSI-IPentCl Precatalyst
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A single set of reaction conditions for the palladium-catalyzed amination of a wide variety of (hetero)aryl halides using primary alkyl amines has been developed. By combining the exceptionally high reactivity of the Pd-PEPPSI-IPentCl catalyst (PEPPSI=pyridine enhanced precatalyst preparation, stabilization, and initiation) with the soluble and nonaggressive sodium salt of BHT (BHT=2,6-di-tert-butyl-hydroxytoluene), both six- and five-membered (hetero)aryl halides undergo efficient and selective amination.
- Sharif, Sepideh,Rucker, Richard P.,Chandrasoma, Nalin,Mitchell, David,Rodriguez, Michael J.,Froese, Robert D. J.,Organ, Michael G.
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supporting information
p. 9507 - 9511
(2015/08/11)
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- CuI/Oxalic Diamide Catalyzed Coupling Reaction of (Hetero)Aryl Chlorides and Amines
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A class of oxalic diamides are found to be effective ligands for promoting CuI-catalyzed aryl amination with less reactive (hetero)aryl chlorides. The reaction proceeds at 120 °C with K3PO4 as the base in DMSO to afford a wide range of (hetero)aryl amines in good to excellent yields. The bis(N-aryl) substituted oxalamides are superior ligands to N-aryl-N′-alkyl substituted or bis(N-alkyl) substituted oxalamides. Both the electronic nature and the steric property of the aromatic rings in ligands are important for their efficiency.
- Zhou, Wei,Fan, Mengyang,Yin, Junli,Jiang, Yongwen,Ma, Dawei
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supporting information
p. 11942 - 11945
(2015/10/06)
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- SiO2-Cu2O: An efficient and recyclable heterogeneous catalyst for N-benzylation of primary and secondary amines
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A mild, effective, and selective procedure is reported for the mono N-benzylation and N,N-dibenzylation of primary amines as well as mono N-benzylation of secondary amines using silica-supported copper(I) oxide in water. The silica-supported Cu2O was generated in situ by the reaction of Fehling solution and glucose at 100 C onto activated silica. The catalyst was filtered, washed with water, and oven-dried, and was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and atomic absorption spectroscopy. The prepared Cu2O-SiO2 was found to be thermally stable up to 325 C. The copper was uniformly distributed onto the surface of the silica, and the mean particle diameter was 7 nm. The catalyst served as a selective heterogenous catalyst for the N-benzylation of primary and secondary amines. The catalyst is recyclable and was used effectively upto fifth run without a significant loss of catalytic activity. Various reaction solvents including water, acetonitrile, and toluene were screened for N-benzylation of amines, and the success of the aqueous system highlights the low environmental impact of the procedure.
- Gupta, Manjulla,Paul, Satya,Gupta, Rajive
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p. 444 - 450
(2014/04/03)
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- Green synthesis and catalytic properties of palladium nanoparticles for the direct reductive amination of aldehydes and hydrogenation of unsaturated ketones
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This paper reports on the synthesis and use of palladium nanoparticles as heterogeneous catalysts for the reductive amination of aldehydes and hydrogenation of unsaturated ketones. This method has the advantages of high yields, simple methodology and easy work up. The catalyst can be recovered and reused several times without significant loss of catalytic activity. This journal is
- Nasrollahzadeh, Mahmoud
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p. 5544 - 5550
(2014/12/10)
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- A recyclable Cu-catalyzed C-N coupling reaction in water and its application to synthesis of imidazo[1,2-a]quinoxaline
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Polystyrene-supported pyrrole-2-carbohydrazide (PSP) was synthesized and combined with CuI to make up a recyclable heterogeneous catalytic system for Ullmann-type C-N coupling reaction in water. In which, a variety of functionalized aryl halides animated efficiently with anilines, benzylamine, aliphatic amines, and imidazole. its preliminary application resulted in a more practical synthesis of imidazo[1,2-a]quinoxaline.
- Huang, Liye,Yu, Ruina,Zhu, Xinhai,Wan, Yiqian
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supporting information
p. 8974 - 8977
(2013/09/23)
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- Copper(I)-catalyzed N-arylation of N1,N3- dibenzylmalonamide and N1,N3-dibutylmalonamide followed by cleavage of the malonyl group with aryl halides under ligand-free conditions
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We primarily developed a practical and convenient protocol to synthesize of aromatic amines based on CuI-catalyzed N-arylation of N1,N 3-dibenzylmalonamide and N1,N3- dibutylmalonamide followed by cleavage of the malonyl group with aryl halides under ligand-free conditions giving good yields.
- Zheng,Xu,Shi,Ren,Lu,Zhou
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p. 1117 - 1122
(2013/05/08)
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- N-Alkylation of amines with alcohols over nanosized zeolite beta
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Direct N-alkylation of amines with alcohols was successfully performed by using nanosized zeolite beta, which showed the highest catalytic activity among other conventional zeolites. This method has several advantages, such as eco-friendliness, moderate to high yields, and simple work-up procedure. The catalyst was successfully recovered and reused without significant loss of activity and only water is produced as co-product. In addition, imines were also efficiently prepared from the tandem reactions of amines with 2-, 3- and 4-nitrobenzyl alcohols using nanosized zeolite beta.
- Reddy, Marri Mahender,Kumar, Macharla Arun,Swamy, Peraka,Naresh, Mameda,Srujana, Kodumuri,Satyanarayana, Lanka,Venugopal, Akula,Narender, Nama
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supporting information
p. 3474 - 3483
(2013/12/04)
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- CuI/DMPAO-catalyzed N-arylation of acyclic secondary amines
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DMPAO has been found to be a powerful ligand to enable copper-catalyzed coupling of aryl halides with aliphatic acyclic secondary amines take place under relatively mild conditions, and coupling of aryl halides with primary amines and cyclic secondary amines proceeds at low catalyst loading.
- Zhang, Yu,Yang, Xinye,Yao, Qizheng,Ma, Dawei
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supporting information; experimental part
p. 3056 - 3059
(2012/07/28)
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- Sulfonated multiwalled carbon nanotubes (MWCNTs) as a new, efficient, and recyclable heterogeneous nanocatalyst for the synthesis of amines
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Sulfonated multiwalled carbon nanotubes (MWCNTs) were synthesized by chemical vapor deposition (CVD) as a new and facile one-pot method using acetylene (as the CNT precursor), thiophene (as the sulfur precursor), and ferrocene (for in situ liberation of metal nanoparticles as the CNT nanocatalyst). A low catalytic amount of the resulting sulfonated MWCNTs with a turnover number (TON) up to 980 and a turnover frequency (TOF) up to 11 160 h-1 was utilized as a new and recyclable heterogeneous nanocatalyst for the efficient one-pot synthesis of various amines (secondary and tertiary) by direct reductive amination of aldehydes and ketones using NaBH4. The catalyst was easily isolated from the reaction mixture by simple filtration and reused at least five times without significant degradation in activity.
- Doroodmand, M. M.,Sobhani, S.,Ashoori, A.
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p. 701 - 707,7
(2020/08/31)
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- Diastereospecific coupling of imines by low-valent titanium: An experimental and Computational study
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The reaction of phenylsilane (PhSiH3) and titanium(IV) isopropoxide [Ti(OiPr)4] generates low-valent titanium alkoxides that reduce and reductively couple imines. The C-C coupling reaction is diastereospecific, with exclusive formati
- Kumar, Akshai,Samuelson, Ashoka G.
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supporting information; experimental part
p. 951 - 959
(2011/04/15)
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