- Nickel-Catalyzed Oxidative Transamidation of Tertiary Aromatic Amines with N -Acylsaccharins
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The use of tertiary amines as surrogates for secondary amines has prominent advantages in terms of stabilization and ease of handling. A Ni-catalyzed transamidation of N -acylsaccharins with tertiary aromatic amines is reported. By using tert -butyl hydroperoxide as the terminal oxidant, this reaction permits selective cleavage of the C(sp 3)-N bonds of unsymmetrical tertiary aromatic amines depending on the sizes of the alkyl substituents.
- Liu, Shengzhang,Yang, Lingyun,Tao, Jiasi,Yu, Weijie,Wang, Tao,Fu, Junkai
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p. 1642 - 1646
(2021/06/21)
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- N-Heterocyclic Carbene/Cobalt Cooperative Catalysis for the Chemo- and Regioselective C?N Bond Formation between Aldehyde and Amines/Amides
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A novel methodology for the construction of various secondary (4 examples), tertiary amides (31 examples), and imides (16 examples) by a Cobalt(II) catalyzed oxidative amide coupling in aqueous media. The Co(III)-TMC was reacted with N-Heteroatom Carbene to form active catalyst Co(II)NHC-TMC in situ which involves in the coordination with Breslow's intermediate and SET for the activation of aldehyde and amides. The mechanism for activation of amide and amine differs on the basis of SET based nucleophilic addition and ligand exchange respectively. The regeneration of the catalyst was achieved using Fe(III)(EDTA)-H2O2 as oxidant. The use of Co(II)TMC-O2 was also found equally efficient in the process. The method is found regioselective for N?H activation in the presence of equally susceptible ortho-C?H bond activation. And amines were found more susceptible then the corresponding amide for the reaction.
- Siddiqui, Asher M.,Khalid, Anam,Khan, Arif,Azad, Chandra S.,Samim, Mohd.,Khan, Imran A.
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p. 4281 - 4287
(2020/07/24)
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- Ultrafast amidation of esters using lithium amides under aerobic ambient temperature conditions in sustainable solvents
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Lithium amides constitute one of the most commonly used classes of reagents in synthetic chemistry. However, despite having many applications, their use is handicapped by the requirement of low temperatures, in order to control their reactivity, as well as the need for dry organic solvents and protective inert atmosphere protocols to prevent their fast decomposition. Advancing the development of air- and moisture-compatible polar organometallic chemistry, the chemoselective and ultrafast amidation of esters mediated by lithium amides is reported. Establishing a novel sustainable access to carboxamides, this has been accomplished via direct C-O bond cleavage of a range of esters using glycerol or 2-MeTHF as a solvent, in air. High yields and good selectivity are observed while operating at ambient temperature, without the need for transition-metal mediation, and the protocol extends to transamidation processes. Pre-coordination of the organic substrate to the reactive lithium amide as a key step in the amidation processes has been assessed, enabling the structural elucidation of the coordination adduct [{Li(NPh2)(OCPh(NMe2))}2] (8) when toluene is employed as a solvent. No evidence for formation of a complex of this type has been found when using donor THF as a solvent. Structural and spectroscopic insights into the constitution of selected lithium amides in 2-MeTHF are provided that support the involvement of small kinetically activated aggregates that can react rapidly with the organic substrates, favouring the C-O bond cleavage/C-N bond formation processes over competing hydrolysis/degradation of the lithium amides by moisture or air.
- Bole, Leonie J.,Fairley, Michael,García-Alvarez, Joaquín,Hevia, Eva,Kennedy, Alan R.,Main, Laura,Mulks, Florian F.,O'Hara, Charles T.
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p. 6500 - 6509
(2020/07/15)
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- Facile amidation of esters with aromatic amines promoted by lanthanide tris (amide) complexes
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The development of catalysts capable of catalyzing amidation of esters with amines to construct amides under mild conditions is of great importance. Compared to aliphatic amines, the direct catalytic amidation of esters with less nucleophilic aromatic amines is rather difficult. Employing simple lanthanide tris (amide) complexes Ln[N (SiMe3)2]3(μ-Cl)Li (THF)3 as the catalysts, it was found a broad range of aromatic amines and esters were efficiently converted into various amides in good yields under mild conditions. A plausible mechanism for this transformation was experimentally supported as starting from an amide exchange reaction between the lanthanide tris (amide) complex and the substrate amine.
- Li, Zhao,Guo, Chenjun,Chen, Jue,Yao, Yingming,Luo, Yunjie
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- Palladium-catalyzed aminocarbonylation of aryl iodides with amides and N-alkyl anilines
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A novel and efficient palladium-catalyzed aminocarbonylation of aryl iodides with amides and N-alkyl anilines has been developed. The reaction tolerates a wide range of functional groups and is a reliable method for the rapid synthesis of a variety of valuable imides and tertiary benzanilides under an atmospheric pressure of CO. Copyright
- Ran, Longfei,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
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p. 577 - 583
(2014/02/14)
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- NBu4NI-catalyzed oxidative amidation of aldehydes with tertiary amines
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An efficient oxidative coupling protocol for amide formation has been developed. Various tertiary amines and aromatic aldehydes were oxidized to their corresponding tertiary amides in moderate to good yields in the presence of a simple nBu4NI-catalyst.
- Wang, Shan,Wang, Jian,Guo, Rui,Wang, Gao,Chen, Shan-Yong,Yu, Xiao-Qi
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supporting information
p. 6233 - 6236
(2013/10/22)
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