20056-60-4Relevant academic research and scientific papers
Nickel-catalyzed coupling reaction of alkyl halides with aryl Grignard reagents in the presence of 1,3-butadiene: Mechanistic studies of four-component coupling and competing cross-coupling reactions
Iwasaki, Takanori,Fukuoka, Asuka,Yokoyama, Wataru,Min, Xin,Hisaki, Ichiro,Yang, Tao,Ehara, Masahiro,Kuniyasu, Hitoshi,Kambe, Nobuaki
, p. 2195 - 2211 (2018)
We describe the mechanism, substituent effects, and origins of the selectivity of the nickel-catalyzed four-component coupling reactions of alkyl fluorides, aryl Grignard reagents, and two molecules of 1,3-butadiene that affords a 1,6-octadiene carbon framework bearing alkyl and aryl groups at the 3- and 8-positions, respectively, and the competing cross-coupling reaction. Both the four-component coupling reaction and the cross-coupling reaction are triggered by the formation of anionic nickel complexes, which are generated by the oxidative dimerization of two molecules of 1,3-butadiene on Ni(0) and the subsequent complexation with the aryl Grignard reagents. The C-C bond formation of the alkyl fluorides with the γ-carbon of the anionic nickel complexes leads to the four-component coupling product, whereas the cross-coupling product is yielded via nucleophilic attack of the Ni center toward the alkyl fluorides. These steps are found to be the rate-determining and selectivity-determining steps of the whole catalytic cycle, in which the C-F bond of the alkyl fluorides is activated by the Mg cation rather than a Li or Zn cation. ortho-Substituents of the aryl Grignard reagents suppressed the cross-coupling reaction leading to the selective formation of the four-component products. Such steric effects of the ortho-substituents were clearly demonstrated by crystal structure characterizations of ate complexes and DFT calculations. The electronic effects of the para-substituent of the aryl Grignard reagents on both the selectivity and reaction rates are thoroughly discussed. The present mechanistic study offers new insight into anionic complexes, which are proposed as the key intermediates in catalytic transformations even though detailed mechanisms are not established in many cases, and demonstrates their synthetic utility as promising intermediates for C-C bond forming reactions, providing useful information for developing efficient and straightforward multicomponent reactions.
Terminal-Selective C(sp3)-H Arylation: NiH-Catalyzed Remote Hydroarylation of Unactivated Internal Olefins
He, Yuli,Han, Bo,Zhu, Shaolin
supporting information, p. 2253 - 2264 (2021/05/05)
A terminal-selective migratory hydroarylation of unactivated olefins has been developed though a NiH-catalyzed alkene isomerization-hydroarylation relay process. This sp3C-H arylation was achieved with a simple pyrox ligand under mild conditions. The practicality and synthetic flexibility of the method is highlighted by the successful regioconvergent conversion of isomeric mixtures of alkenes to value-added linear arylation products on a gram scale.
Nickel-Catalyzed Reductive Cross-Coupling of Aryl Halides with Monofluoroalkyl Halides for Late-Stage Monofluoroalkylation
Sheng, Jie,Ni, Hui-Qi,Zhang, Hao-Ran,Zhang, Kai-Fan,Wang, Yi-Ning,Wang, Xi-Sheng
supporting information, p. 7634 - 7639 (2018/06/26)
A combinatorial nickel-catalyzed monofluoroalkylation of aryl halides with unactivated fluoroalkyl halides by reductive cross-coupling has been developed. This method demonstrated high efficiency, mild conditions, and excellent functional-group tolerance, thus enabling the late-stage monofluoroalkylation of diverse drugs. The key to success was the combination of diverse readily available bidentate and monodentate pyridine-type nitrogen ligands with nickel, which in situ generated a variety of readily tunable catalysts to promote fluoroalkylation with broad scope with respect to both coupling partners. This combinatorial catalysis strategy offers a solution for nickel-catalyzed reductive cross-coupling reactions and provides an efficient way to synthesize fluoroalkylated druglike molecules for drug discovery.
Aryl Ketones as Single-Electron-Transfer Photoredox Catalysts in the Nickel-Catalyzed Homocoupling of Aryl Halides
Masuda, Yusuke,Ishida, Naoki,Murakami, Masahiro
supporting information, p. 5822 - 5825 (2016/12/18)
An intriguing photoredox system for the homocoupling of aryl halides is reported wherein thioxanthone catalyzes a single-electron transfer from an amine reductant to nickel.
Cobalt-catalyzed cross-coupling reactions of aryl bromides with alkyl grignard reagents
Hamaguchi, Hiroyuki,Uemura, Minoru,Yasui, Hiroto,Yorimitsu, Hideki,Oshima, Koichiro
experimental part, p. 1178 - 1179 (2011/02/28)
Aryl bromides react with primary alkyl Grignard reagents in the presence of N,N,N′,N′-tetramethyl-1,3-propanediamine and catalytic amounts of cobalt(II) chloride and an N-heterocyclic carbene to yield the corresponding cross-coupling products in high yields. Copyright
