18434-12-3Relevant articles and documents
Scope, Kinetics, and Mechanism of “On Water” Cu Catalysis in the C–N Cross-Coupling Reactions of Indole Derivatives
Malavade, Vrunda,Patil, Manish,Patil, Mahendra
supporting information, p. 561 - 569 (2020/02/05)
A simple and cost-effective protocol for the C–N cross coupling of indole derivatives with aryl iodides using CuI/phenanthroline catalytic system in aqueous and DME/H2O solvent mixture is described. The reactions were performed in the absence of phase-transfer catalyst, and afforded N-arylated products in moderate to excellent yields under mild reaction conditions. A systematic tuning of reaction conditions using DME as a co-solvent enables to improve product yields of N-arylation reactions. The broad substrate scope, easy performance, and low loading of catalyst as well as ligand render this approach appropriate for large scale processes. The mechanism of “on water” Cu-catalyzed N-arylation reaction is investigated using kinetic and computational studies, which reveal interesting mechanistic aspects of the reaction. A series of kinetic experiments showed significant rate enhancement for “on water” Cu-catalyzed N-arylation over the reaction performed in the organic solvent (DME). Computational studies corroborated “on water” rate acceleration by delineating the role of water in the reaction. The water induces rate acceleration by stabilizing the transition state of oxidative addition through hydrogen bonding interactions, presumably at the oil-water interface, and thus helps to reduce the free energy of activation of oxidative addition of iodobenzene to the Cu complex, which is identified as the rate-limiting step of reaction.
Palladium-Catalyzed C-N Cross-Coupling of NH-Heteroarenes and Quaternary Ammonium Salts via C-N Bond Cleavage
Chen, Hongyi,Yang, Hongqin,Li, Nutao,Xue, Xinghua,He, Ze,Zeng, Qingle
, p. 1679 - 1685 (2019/08/20)
In this paper, we extend the substrate class of Buchwald-Hartwig amination to quaternary ammonium salts. In the presence of Pd(OAc)2 and t-BuXPhos, the coupling of aryl- or arylmethyltrimethylammonium triflates with NH-heteroarenes via C-N bond cleavage affords the desired N-aryl or N-arylmethyl heteroarenes in moderate to excellent yields.
CNT-CuO catalyzed C–N bond formation for N-arylation of 2-phenylindoles
Lim, Jeongah,Kim, Ji Dang,Choi, Hyun Chul,Lee, Sunwoo
supporting information, (2019/10/14)
Carbon nanotube–copper oxide (CNT–CuO) nanocomposites were prepared by depositing CuO nanoparticles onto functionalized CNT surfaces. The structure and elemental content of CNT–CuO were characterized using transmission electron microscopy, X-ray diffraction, and Auger electron spectroscopy. The prepared CNT-CuO was subsequently employed as a catalyst for the coupling reaction of 2-phenylindole with aryl iodides to provide the desired N-aryl 2-phenylindoles in good yields.