1517-46-0Relevant articles and documents
Palladium-Catalyzed Desulfurative Hiyama Coupling of Thioureas to Achieve Amides via Selective C-N Bond Cleavage
He, Zhanyu,Yan, Chu,Zhang, Mei,Irfan, Majeed,Wang, Zijia,Zeng, Zhuo
supporting information, p. 705 - 710 (2021/10/25)
Palladium-catalyzed Hiyama coupling of active thioureas via selective C-N bond cleavage is reported. Notably, the new approach employed active thioureas as coupling partners in the presence of arylsilanes to give amides in good yield. Further, this strategy, which utilized CuF 2as a key oxidant and activator, afforded various amide products under mild conditions and an easy to handle procedure without extra base.
Nickel-Catalyzed Oxidative Transamidation of Tertiary Aromatic Amines with N -Acylsaccharins
Liu, Shengzhang,Yang, Lingyun,Tao, Jiasi,Yu, Weijie,Wang, Tao,Fu, Junkai
supporting information, p. 1642 - 1646 (2021/06/21)
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.
Copper-Catalyzed Radical N-Demethylation of Amides Using N-Fluorobenzenesulfonimide as an Oxidant
Yi, Xuewen,Yi, Xuewen,Lei, Siyu,Liu, Wangsheng,Che, Fengrui,Yu, Chunzheng,Liu, Xuesong,Wang, Zonghua,Zhou, Xin,Zhang, Yuexia
supporting information, p. 4583 - 4587 (2020/05/05)
An unprecedented N-demethylation of N-methyl amides has been developed by use of N-fluorobenzenesulfonimide as an oxidant with the aid of a copper catalyst. The conversion of amides to carbinolamines involves successive single-electron transfer, hydrogen-atom transfer, and hydrolysis, and is accompanied by formation of N-(phenylsulfonyl)benzenesulfonamide. Carbinolamines spontaneously decompose to N-demethylated amides and formaldehyde, because of their inherent instability.
Facile amidation of esters with aromatic amines promoted by lanthanide tris (amide) complexes
Li, Zhao,Guo, Chenjun,Chen, Jue,Yao, Yingming,Luo, Yunjie
, (2020/02/04)
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.
N-Heterocyclic Carbene/Cobalt Cooperative Catalysis for the Chemo- and Regioselective C?N Bond Formation between Aldehyde and Amines/Amides
Siddiqui, Asher M.,Khalid, Anam,Khan, Arif,Azad, Chandra S.,Samim, Mohd.,Khan, Imran A.
, p. 4281 - 4287 (2020/07/24)
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.
Ultrafast amidation of esters using lithium amides under aerobic ambient temperature conditions in sustainable solvents
Bole, Leonie J.,Fairley, Michael,García-Alvarez, Joaquín,Hevia, Eva,Kennedy, Alan R.,Main, Laura,Mulks, Florian F.,O'Hara, Charles T.
, p. 6500 - 6509 (2020/07/15)
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.
An efficient synthesis of benzothiazole using tetrabromomethane as a halogen bond donor catalyst
Kazi, Imran,Sekar, Govindasamy
, p. 9743 - 9756 (2019/12/02)
An efficient and mild protocol has been developed for the synthesis of 2-substituted benzothiazole under solvent- and metal-free conditions using CBr4 as the catalyst. This process involves the activation of a thioamide through halogen bond formation between the sulphur atom of the thioamide and bromine atom of the CBr4 molecule. The presence of halogen-bonding interaction between N-methylthioamides and tetrabromomethane has been demonstrated with several control experiments, spectroscopic analysis and density functional theory (DFT). This methodology has a wide substrate scope for the synthesis of both 2-alkyl and 2-aryl substituted benzothiazoles.
Enantioselective Desymmetrization of cis-3,5- O-Arylidenecyclohexanones Catalyzed by Cinchona-Derived Quaternary Ammonium Salts
Cortigiani, Mauro,Gillick Healy, Malachi,Mereu, Andrea,Adamo, Mauro F. A.
, p. 4112 - 4119 (2019/04/30)
An enantioselective protocol for the desymmetrization of cis-3,5-O-arylidenecyclohexanones has been developed that proceeded under the catalysis of readily available and inexpensive Cinchona-derived quaternary ammonium salts. The synthetic relevance of the methodology was exemplified by the synthesis of a key intermediate that could be used in the preparation of the active pharmaceutical ingredient, paricalcitol (Zemplar).
KMnO4-mediated oxidative C[sbnd]N bond cleavage of tertiary amines: Synthesis of amides and sulfonamides
Zhang, Zhang,Liu, Yong-Hong,Zhang, Xi,Wang, Xi-Cun
, p. 2763 - 2770 (2019/04/10)
KMnO4-mediated oxidative C[sbnd]N bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.
Gram-Scale, Cheap, and Eco-Friendly Iron-Catalyzed Cross-Coupling between Alkyl Grignard Reagents and Alkenyl or Aryl Halides
Cahiez, Gérard,Lefèvre, Guillaume,Moyeux, Alban,Guerret, Olivier,Gayon, Eric,Guillonneau, Lo?c,Lefèvre, Nicolas,Gu, Qinzhuo,Zhou, Edouard
supporting information, p. 2679 - 2683 (2019/04/30)
A new robust methodology for gram-scale iron-catalyzed cross-coupling between alkyl Grignard reagents and alkenyl or aryl halides is developed. This method does not require toxic additives such as NMP or expensive ligands. Its efficiency relies on the use of simple alkoxide magnesium salts as additives. On the basis of these results, a new procedure for one-pot synthesis of substituted benzamides from chloroesters is also proposed.
