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A Theoretical Insight into the Mechanism of Cu(I)‐Catalyzed CN Coupling between Aryl Halides and Aqueous Ammonia
Author(s) -
Chen Ting,
Yan Mingkuan,
Zheng Chao,
Yuan Jie,
Xu Shen,
Chen Runfeng,
Huang Wei
Publication year - 2015
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201500267
Subject(s) - chemistry , deprotonation , catalysis , catalytic cycle , amination , ligand (biochemistry) , aryl , reductive elimination , halide , aqueous solution , bromide , ammonia , oxidative addition , exothermic reaction , reaction mechanism , combinatorial chemistry , medicinal chemistry , inorganic chemistry , organic chemistry , alkyl , receptor , ion , biochemistry
Computational investigations of Cu(I)‐catalyzed CN coupling between aryl halides and aqueous ammonia without addition of any base or ligand were reported. Density functional theory calculations were performed to reveal the mechanism of the ligand‐free amination reaction for the preparation of primary aromatic amines. Through systematic evaluation of the relative concentrations of possible Cu species in solution, we propose that the active catalyst is the neutral Cu(I) complexes rather than the Cu(I) cations; oxidative addition of aryl bromide is a facile step of the catalytic cycle; reactant (NH 3 ) and solvent molecule (NMP) can act as ligands of Cu species to help reduce the activation energy of the forward reaction and increase the activation energy of the reverse reaction; except for Pathway B, the deprotonation step is irreversible due to the extreme exothermic feature; the elimination of H 2 O is kinetically favored, while that of HBr is thermodynamically preferred. These findings should be valuable for the mechanism understandings of the ligand‐free Cu‐catalyzed CN cross‐coupling reactions and for the further development of highly efficient amination catalyst systems.