Highly efficient copper catalytic system for the O-arylation of phenol with iodoarene

Picolinamides as Effective Ligands for Copper‐Catalysed Aryl Ether Formation: Structure–Activity Relationships, Substrate Scope and Mechanistic Investigations

“…This effect was further demonstrated by the synthesis of compounds 30 – 33 , bearing increasingly bulky ortho substituents, obtained in 52–81 % yields. Strong sensitivity to the steric hindrance on the aryl iodide (see also compound 38 , Scheme a), but not (or to a much lesser extent) to that on the phenol, was also observed by Hsieh and Ma using different systems 67. 69 Couplings with hindered phenols and deactivated iodoanisole, or with indazole precursors, were also accomplished in very good yields ( 34 – 36 ; see also compound 41 , Scheme b).…”

Chemoselective and ligand-free synthesis of diaryl ethers in aqueous medium using recyclable alumina-supported nickel nanoparticles

“…Haloarenes 2d and 2e with electron donating substituents (which are less susceptible to nucleophilic attack) required a little higher temperature (100 0 C) and longer reaction time (10 hours) to react with 1a and yielded 3m and 3n with 76% and 78% respectively. The present method was extended to the reactions of 2-halopyridines and with phenols bearing chloro and methyl groups as the substituents, where the corresponding 2-aryloxypyridines were produced in quite good yield (entries [16][17][18][19]. As before, the reactions went fine with both 2-bromo-as well as 2-chloropyridines.…”

“…9,10 The most straightforward way to synthesise diaryl ethers is either palladium or copper catalysed coupling reaction between aryl halides and phenols. The harsh conditions of classical Ullmann synthesis have limitations due to involvement of stoichiometric amounts of copper reagents with some extra ligands, [11][12][13][14][15][16][17][18][19][20] requirement of high temperatures along with long reaction time, 11,13-20-22 and use of moisture sensitive, costly base 11,[13][14][15][16]18,19,22 as well as employment of inert atmosphere. [11][12][13]15,16,18,[21][22][23][24] For this reason, immense efforts have been spent in past few years for the discovery of more attractive and utilitarian arylation methods.…”

A Cu Nanoparticle Embedded in Electrospundoped Carbon Nanofibers as Efficient Catalysts for Ullmann O-Arylation of Aryl Halides with Various Phenols

“…Kidwai et al reported that Cu-nanoparticle catalyzed O-arylation of phenols with aryl halides via Ullmann coupling [36]. An efficient Cu-catalyzed O-arylation of phenol with iodoarene was reported by Cheng et al [37]. In many cases, Cu catalyzed Ullmann arylation reaction works well without any ligands, and the ligands are usually structurally quite simple and cheaper when they are required [38].…”