Selective copper catalysed aromatic N-arylation in water

Green alternative solvents for the copper-catalysed arylation of phenols and amides

“…17,21 Water is frequently used as a co-solvent for these processes in mixtures with DMSO or DMF. When water alone is used, the addition of a phase-transfer catalyst (PTC), 22 a polymeric additive, 23 or a surfactant 24 is often required for effective catalysis. A further disadvantage is the use of hydroxides as bases in these conditions, rather than carbonates or phosphates; these bases are known to be able to react with the aryl halide as nucleophiles, thus leading to the corresponding phenolic side products.…”

Scope, Kinetics, and Mechanism of “On Water” Cu Catalysis in the C–N Cross‐Coupling Reactions of Indole Derivatives

“…The reaction gave only 23 % of product when it was carried out in neat DME as a solvent (entry 9). The use of other organic solvents (DMSO, DMF and toluene) as co-solvent in the model reaction was not as effective as DME (entries [10][11][12][13][14]. The reactions with other substrates in DME/H 2 O solvent system were also performed to probe the generality of this method.…”

“…In order to overcome poor solubility issue, reactions involving aqueous medium are often carried out in the presence of surfactants or phase‐transfer catalyst (PTC). Recently, Fu et al reported copper‐catalyzed N‐arylation of NH‐heteroarene in water using oxaldehyde dioxime as a ligand and tetrabutylammonium bromide as a phase‐transfer catalyst, whereas Ulven et al demonstrated the use of 4,7‐dipyrrolidinyl‐1,10‐phenanthroline (DPPhen) as a ligand and PEG‐400 as a surfactant for the copper catalyzed N‐arylation in water . The bidentate ligands, which have been successfully employed in the aqueous medium, are shown in Scheme .…”

“…[1,2] In contrast, the use of aqueous media for the Cu-catalyzed C-N bond forming reactions is very rarely described. [4][5][6][7][8][9][10][11][12][13][14] The poor solubility of organic materials and rapid decomposition of reactive intermediates in water is assumed to be detrimental to achieve a high catalytic efficiency in water. In order to overcome poor solubility issue, reactions involving aqueous medium are often carried out in the presence of surfactants or phase-transfer catalyst (PTC).…”

Preparation, Characterization and Application of Copper Schiff base Complex Supported on MCM‐41 as a Recyclable Catalyst for the Ullmann‐type N‐arylation Reaction

“…The most promising method in the literature for the N‐arylation reaction is Copper‐catalyzed Ullmann‐type transformation. Unfortunately, this method requires a stoichiometric amount of copper catalyst at high temperatures, which eventually produce a large amount of hazardous copper‐based waste and are thus not considered to be environmentally benign and economic processes . To circumvent this issue, many attempts have been made to develop efficient catalytic systems by introducing new and efficient ligands …”