28593-20-6Relevant 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 (2018/03/05)
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.
Nickel-Catalyzed Dimerization and Alkylarylation of 1,3-Dienes with Alkyl Fluorides and Aryl Grignard Reagents
Iwasaki, Takanori,Min, Xin,Fukuoka, Asuka,Kuniyasu, Hitoshi,Kambe, Nobuaki
supporting information, p. 5550 - 5554 (2016/05/09)
In the presence of a nickel catalyst, 1,3-butadiene undergoes selective dimerization and alkylarylation with alkyl fluorides and aryl Grignard reagents to give 1,6-octadienes with alkyl and aryl groups at the 3- and 8-positions, respectively, by the consecutive formation of three carbon-carbon bonds. The formation of an anionic nickel complex plays an important role in forming C-C bonds with alkyl fluorides.
Dinuclear iron complex-catalyzed cross-coupling of primary alkyl fluorides with aryl grignard reagents
Mo, Zhenbo,Zhang, Qiang,Deng, Liang
, p. 6518 - 6521 (2012/10/29)
Iron-catalyzed cross-coupling of nonactivated primary alkyl fluorides with aryl Grignard reagents has been achieved by using the low-coordinate dinuclear iron complex [(IPr2Me2)Fe(μ2-NDipp) 2Fe(IPr2Me2)] as the catalyst. This iron-catalyzed C(sp3)-F bond arylation reaction is applicable to a variety of aryl Grignard reagents and primary alkyl fluorides. The product pattern suggests the involvement of a radical-type mechanism for its C-F bond scission step.
POLYCYCLIC RING-FUSED COMPOUND AND ORGANIC THIN FILM TRANSISTOR UTILIZING SAME
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Page/Page column 25, (2012/11/08)
A compound for an organic thin film transistor represented by the following formula (1):
Iron(II) complexes with functionalized amine-pyrazolyl tripodal ligands in the cross-coupling of aryl Grignard with alkyl halides
Xue, Fei,Zhao, Jin,Hor, T. S. Andy
experimental part, p. 8935 - 8940 (2011/10/19)
Structurally distinctive Fe(ii) complexes with furan, thiophene and pyridine functionalized amine-pyrazolyl tripodal hybrid ligands have been synthesized and crystallographically characterized. The tether substituent at the central amine plays an active role in determining the coordination mode of the ligand and the metal geometry. All complexes are catalytically active towards cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides with β-hydrogen under ambient conditions. ESI-MS spectra analysis revealed the ligand-stabilised Fe(ii) and Mg(ii) species. The Royal Society of Chemistry 2011.
Functional group tolerant Kumada-Corriu-Tamao coupling of nonactivated alkyl halides with aryl and heteroaryl nucleophiles: Catalysis by a nickel pincer complex permits the coupling of functionalized Grignard reagents
Vechorkin, Oleg,Proust, Valerie,Hu, Xile
supporting information; experimental part, p. 9756 - 9766 (2011/03/19)
A nickel(II) pincer complex [(MeNN2)NiCl] (1) catalyzes Kumada-Corriu-Tamao cross coupling of nonactivated alkyl halides with aryl and heteroaryl Grignard reagents. The coupling of octyl bromide with phenylmagnesium chloride was used as a test reaction. Using 3 mol % of 1 as the precatalyst and THF as the solvent, and in the presence of a catalytic amount of TMEDA, the coupling product was obtained in a high yield. The reaction conditions could be applied to cross coupling of other primary and secondary alkyl bromides and iodides. The coupling is tolerant to a wide range of functional groups. Therefore, alkyl halides containing ester, amide, ether, thioether, alcohol, pyrrole, indole, furan, nitrile, conjugated enone, and aryl halide moieties were coupled to give high isolated yields of products in which these units stay intact. For the coupling of ester-containing substrates, O-TMEDA is a better additive than TMEDA. The reaction protocol proves to be efficient for the coupling of Knochel-type functionalized Grignard reagents. Thus aryl Grignard reagents containing electron-deficient and/or sensitive ester, nitrile, amide, and CF3 substituents could be successfully coupled to nonactivated and functionalized alkyl iodides. The catalysis is also efficient for the coupling of alkyl iodides with functionalized heteroaryl Grignard reagents, giving rise to pyridine-, thiophene-, pyrazole-, furan-containing molecules with additional functionalities. Concerning the mechanism of the catalysis, [(MeNN2)Ni-(hetero)Ar] was identified as an intermediate, and the activation of alkyl halides was found to take place through a radical-rebound process.
Iron-catalyzed grignard cross-coupling with alkyl halides possessing β-hydrogens
Nagano, Takashi,Hayashi, Tamio
, p. 1297 - 1299 (2007/10/03)
Tris(acetylacetonato)iron(III) (Fe(acac)3) was found to be an efficient catalyst for the cross-coupling reaction between aryl Grignard reagents and alkyl halides possessing β-hydrogens. The reaction is applicable to secondary alkyl halides as well as primary ones.
Tetraphosphine/palladium catalysed Suzuki cross-coupling reactions of aryl halides with alkylboronic acids
Kondolff, Isabelle,Doucet, Henri,Santelli, Maurice
, p. 3813 - 3818 (2007/10/03)
Through the use of [PdCl(C3H5)]2/cis,cis, cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides and chlorides undergoes Suzuki cross-coupling with alkylboronic acids in good yields. Several alkyl substituents such as ethyl, n-butyl, n-octyl, isobutyl or 2,2-dimethylpropyl on the alkylboronic acids have been successfully used. The functional group tolerance on the aryl halide is remarkable; substituents such as fluoro, methyl, methoxy, acetyl, formyl, benzoyl, nitro or nitrile are tolerated. Furthermore, this catalyst can be used at low loading, even for reactions of sterically hindered aryl bromides.
Synthesis of 1-Arylalk-2-enes and 1-Arylalkanes via Friedel-Crafts Alkylation with Allylic Alcohols Catalysed by an Acidic Clay
Smith, Keith,Pollaud, Guy M
, p. 3519 - 3520 (2007/10/02)
Moderately activated benzenoid compounds undergo alkylation with allylic alcohols in the presence of acidic K10 clay to give almost exclusively 1-arylalk-2-enes by attack at the terminal position of the intermediate allyl cation; catalytic hydrogenation yields the corresponding 1-arylalkanes.
