Nickel-catalyzed direct C–H arylation of unactivated arenes with aryl halides

NiCl2·6H2O: an efficient catalyst precursor for phosphine-free Heck and Sonogashira cross-coupling reactions

“…Furthermore, a catalyst system consisting of Ni/triphenylphosphine trisulfonate in ethylene glycol film supported on high surface area silica was reported in heterogenizing the Heck reaction [24]. Numerous subsequent reports have been disclosed on a wide variety of different nickel-catalyzed processes [25][26][27][28][29][30]; nevertheless, in contrast to other cross coupling reactions, the application of nickel catalysts in the Heck-type reaction is rare and requires more investigation.…”

Direct Arylation of Benzene with Aryl Bromides using High‐Temperature/High‐Pressure Process Windows: Expanding the Scope of CH Activation Chemistry

“…[2] Importantly, following a recent trend toward more sustainable concepts in catalysis, [3] the number of publications describing readily available first-row transition-metal catalysts for these direct arylations has dramatically increased during the last two years. [4][5][6][7][8][9][10][11][12][13][14][15] Thus, several catalysts based on inexpensive Cu, [4,5] Co, [6,7] Fe, [8][9][10][11][12][13] and Ni [14,15] systems have been demonstrated to be able to promote CÀH bond arylations of this type in the presence of a base. In addition, transition-metal-free organocatalytic protocols, using either 1,10-phenanthroline (phen) derivatives, [16,17] N,N-dimethylethane-1,2-diamine (DMEDA), [18] or quinoline-1-amino-carboxylic acid, [19] have been disclosed.…”

“…In addition, transition-metal-free organocatalytic protocols, using either 1,10-phenanthroline (phen) derivatives, [16,17] N,N-dimethylethane-1,2-diamine (DMEDA), [18] or quinoline-1-amino-carboxylic acid, [19] have been disclosed. [20] From a mechanistic point of view, when aryl halides react with simple arenes to form biaryls, the mechanism has been proposed to follow a radical pathway involving a single-electron-transfer step, [6,7,[12][13][14][15][16][17][18][19] also called "homolytic aromatic substitution" (HAS). [21] Similar biaryl formations using conventional radical-type reagents, such as tris(trimethylsilyl)silane (TTMSS), either alone [22] or in combination with azobis-isobutyronitrile (AIBN), [23] are also known.…”

“…However, for all of the reported first-row transitionmetal-catalyzed [4][5][6][7][8][9][10][11][12][13][14][15] and organocatalytic direct arylation methods, [16][17][18][19] long reaction times (2-48 h) in combination with high catalyst and base loadings are required, clearly limiting the practical use of these otherwise appealing synthetic methods. In the present paper, we explore the concept of high-temperature/high-pressure (high-T/p) process windows [24] for the rapid discovery and screening of novel catalyst/ligand/base combinations in these direct arylation/C À H activation processes, employing a dedicated high-throughput/parallel experimentation platform.…”

Transition‐Metal‐Free Glucose‐Derived Carbonaceous Catalyst Catalyzes Direct C‐H Arylation of Unactivated Arenes with Aryl Halides

“… Abstract Transition metal free coupling reactions have gained lot of importance recently. The traditional method for the synthesis of biaryl's uses organometallic reagents for the arylation reactions . There are certain drawbacks associated with such traditional methods.…”