- DBU-Catalyzed Selective N-Methylation and N-Formylation of Amines with CO2 and Polymethylhydrosiloxane
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We describe herein an efficient organocatalytic system for the selective N-methylation and N-formylation of amines with carbon dioxide (CO2) as a sustainable C1 feedstock and polymethylhydrosiloxane (PMHS) as a cost-effectvie reducing reagent. High-yielding N-methylation products are obtained with low catalyst loading (1%) of DBU. Selective N-formylation of amines is achieved using the same catalytic system at a lower reaction temperature. (Figure presented.).
- Li, Gang,Chen, Jie,Zhu, Dao-Yong,Chen, Ye,Xia, Ji-Bao
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supporting information
p. 2364 - 2369
(2018/05/07)
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- Diverse catalytic reactivity of a dearomatized PN3P?-nickel hydride pincer complex towards CO2 reduction
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A dearomatized PN3P?-nickel hydride complex has been prepared using an oxidative addition process. The first nickel-catalyzed hydrosilylation of CO2 to methanol has been achieved, with unprecedented turnover numbers. Selective methylation and formylation of amines with CO2 were demonstrated by such a PN3P?-nickel hydride complex, highlighting its versatile functions in CO2 reduction.
- Li, Huaifeng,Gon?alves, Théo P.,Zhao, Qianyi,Gong, Dirong,Lai, Zhiping,Wang, Zhixiang,Zheng, Junrong,Huang, Kuo-Wei
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supporting information
p. 11395 - 11398
(2018/10/20)
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- Synthesis, characterization and catalytic activity of stable [(NHC)H][ZnXY2] (NHC?=?N-Heterocyclic carbene, X, Y?=?Cl, Br) species
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The synthesis and characterization of imidazol(in)ium-based zinc(II) halide salts are reported. These compounds present interesting structural features and exhibit high stability. Their catalytic activity was explored in the methylation of amines with CO2 and PhSiH3.
- Santoro, Orlando,Nahra, Fady,Cordes, David B.,Slawin, Alexandra M.Z.,Nolan, Steven P.,Cazin, Catherine S.J.
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- N-heterocyclic carbene copper(i) catalysed N-methylation of amines using CO2
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The N-methylation of amines using CO2 and PhSiH3 as source of CH3 was efficiently performed using a N-heterocyclic carbene copper(i) complex. The methodology was found compatible with aromatic and aliphatic primary and secondary amines. Synthetic and computational studies have been carried out to support the proposed reaction mechanism for this transformation.
- Santoro, Orlando,Lazreg, Fama,Minenkov, Yury,Cavallo, Luigi,Cazin, Catherine S. J.
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p. 18138 - 18144
(2015/10/28)
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- Expanding the Ligand Framework Diversity of Carbodicarbenes and Direct Detection of Boron Activation in the Methylation of Amines with CO2
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A simple and convergent synthetic strategy used to increase the diversity of the carbodicarbene ligand framework through incorporation of unsymmetrical pendant groups is reported. Structural analysis and spectroscopic studies of ligands and their Rh complexes are reported. Reactivity studies reveal carbodicarbenes as competent organocatalysts for amine methylation using CO2 as a synthon. A unique B-H-activated boron-carbodicarbene complex was isolated as a reaction intermediate, providing mechanistic insight into the CO2 functionalization process.
- Chen, Wen-Ching,Shen, Jiun-Shian,Jurca, Titel,Peng, Chun-Jung,Lin, Yen-Hsu,Wang, Yi-Ping,Shih, Wei-Chih,Yap, Glenn P. A.,Ong, Tiow-Gan
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supporting information
p. 15207 - 15212
(2016/01/25)
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- Metal-free catalyst for the chemoselective methylation of amines using carbon dioxide as a carbon source
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N-methylation of amines is an important step in the synthesis of many pharmaceuticals and has been widely applied in the preparation of other key intermediates and chemicals. Therefore, the development of efficient methylation methods has attracted considerable attention. In this respect, carbon dioxide is an attractive C1 building block because it is an abundant, renewable, and nontoxic carbon source. Consequently, we developed a highly chemoselective, metal-free catalytic system that operates under ambient conditions for the N-methylation of amines. The methylation of amines with CO2 as C1 source and Ph2SiH2 as reducing agent was achieved with an N-heterocyclic carbene (NHC) as the catalyst. The catalyst is tolerant toward a variety of functional groups (including esters and ethers, nitro, nitrile, and carbonyl groups, and unsaturated C-C bonds); the reaction uses commercially available reagents and can be performed on a gram scale.
- Das, Shoubhik,Bobbink, Felix D.,Laurenczy, Gabor,Dyson, Paul J.
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supporting information
p. 12876 - 12879
(2016/02/18)
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- Carbon Dioxide Reduction to Methylamines under Metal-Free Conditions
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The first metal-free catalysts are reported for the methylation of amines with carbon dioxide. Proazaphosphatrane superbases prove to be highly active catalysts in the reductive functionalization of CO2, in the presence of hydroboranes. The new methodology enables the methylation of N-H bonds in a wide variety of amines, including secondary amines, with increased chemoselectivity. Organocatalysis: Proazaphosphatrane superbases prove to be highly active catalysts in the reductive functionalization of CO2, in the presence of hydroboranes. The new method makes possible the methylation of N-H bonds in a wide variety of amines, including secondary amines (see picture), with increased chemoselectivity.
- Blondiaux, Enguerrand,Pouessel, Jacky,Cantat, Thibault
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p. 12186 - 12190
(2016/02/23)
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- A general catalytic methylation of amines using carbon dioxide
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Putting CO2 to work: Carbon dioxide is shown to be a general and selective methylating reagent for secondary and primary, aromatic and aliphatic amines under reductive conditions. A variety of tertiary amines are obtained from CO2 and commercially available silanes in high yields with good tolerance to nitrile, olefin, ether, ester, and hydroxy groups. Copyright
- Li, Yuehui,Fang, Xianjie,Junge, Kathrin,Beller, Matthias
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p. 9568 - 9571
(2013/09/23)
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- Selective methylation of amines with carbon dioxide and H2
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Put a label on it: Carbon dioxide with H2 is shown to be an efficient and selective methylation reagent for aromatic and aliphatic amines (see scheme; acac=acetylacetonate, triphos = 1,1,1- tris(diphenylphosphanylmethyl)ethane). A variety of functionalized amines including 13C-labelled drugs were obtained with good yields and functional-group tolerance. Copyright
- Li, Yuehui,Sorribes, Ivan,Yan, Tao,Junge, Kathrin,Beller, Matthias
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supporting information
p. 12156 - 12160
(2013/12/04)
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- Synthesis and photoinitiating properties of N-substituted 2,6-diisopropylanilines
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Reactions of 2,6-diisopropylaniline and its 4-bromo and 4-thiocyanato derivatives with methyl iodide in dimethylformamide in the presence of potassium carbonate gave exclusively the corresponding N,N-dimethyl-substituted products. Heating of 2,6-diisopropylaniline and 2,6-diisopropyl-4-thiocyanatoaniline with methyl iodide without a solvent afforded only N-methyl derivatives. Pleiades Publishing, Ltd., 2011.
- Kolchina,Shekleina,Shelkovnikov
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experimental part
p. 855 - 861
(2011/10/02)
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- Revisitation of Formaldehyde Aniline Condensation. VIII. - Monomeric N-Methylene Anilines
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A convenient, high yield "dry" method of synthesis of monomeric N-methyleneanilines (6a-i) and the characterization of the products by m.s., 1H- and 13C-n.m.r. and i.r. are reported, improving previous procedures and describing new compounds.It appeared that the existence of monomeric N-methyleneanilines is stricly related to the presence of enough steric hindrance to oligomerization by substituents in ortho positions.Moreover, some addition products of formaldehyde to an amine and its corresponding imines are tentatively identified on the basis of the observed mass spectrum of the whole reaction mixture.The reaction products of formaldehyde with 2,6-dimethylaniline (1a) provided an example of a mobile equilibrium between monomeric and trimeric imine.
- Giumanini, Angelo G.,Verardo, Giancarlo,Polana, Marco
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p. 161 - 174
(2007/10/02)
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- Observation of a Stable Monomeric N-Methylene Aromatic Amine
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The first free N-methyleneaniline stable under ordinary conditions was authenticated by spectroscopic and analytical data and some of its reactions were observed; a room temperature equilibrium between another free N-methylene aromatic amine and its oligomeric species is reported.
- Verardo, Giancarlo,Cauci, Sabina,Giumanini, Angelo G.
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p. 1787 - 1788
(2007/10/02)
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