43008-81-7Relevant academic research and scientific papers
Ligand-Controlled Regiodivergence in Nickel-Catalyzed Hydroarylation and Hydroalkenylation of Alkenyl Carboxylic Acids**
Deng, Ruohan,Engle, Keary M.,Fu, Yue,Gao, Yang,Li, Zi-Qi,Liu, Peng,Tran, Van T.
, p. 23306 - 23312 (2020/10/19)
A nickel-catalyzed regiodivergent hydroarylation and hydroalkenylation of unactivated alkenyl carboxylic acids is reported, whereby the ligand environment around the metal center dictates the regiochemical outcome. Markovnikov hydrofunctionalization products are obtained under mild ligand-free conditions, with up to 99 % yield and >20:1 selectivity. Alternatively, anti-Markovnikov products can be accessed with a novel 4,4-disubstituted Pyrox ligand in excellent yield and >20:1 selectivity. Both electronic and steric effects on the ligand contribute to the high yield and selectivity. Mechanistic studies suggest a change in the turnover-limiting and selectivity-determining step induced by the optimal ligand. DFT calculations reveal that in the anti-Markovnikov pathway, repulsion between the ligand and the alkyl group is minimized (by virtue of it being 1° versus 2°) in the rate- and regioselectivity-determining transmetalation transition state.
Effects of substituents on NMR chemical shifts and mass fragmentation patterns of 1-aryl-3-phenylpropanes
Jeong, Eun Jeong,Lee, In-Sook Han
, p. 538 - 543 (2016/04/26)
The 1H and 13C chemical shifts and the mass spectral fragmentation patterns of 1-aryl-3-phenylpropanes with m- or p-substituents (H, NO2, Br, Cl, OCH3, CH3) were studied. The electronic effects of the substi-tuents seemed to be transmitted by the through-space as well as by a through-bond mechanism, resulting in an inverse correlation in the plot of the chemical shift values of i-C vs. the Hammett σ values. The mass spectra showed the substituted benzyl fragments as the base peaks when the substituents were electron donating, whereas the benzyl fragment was observed as the base peaks with the electron-withdrawing substituents.
Indium(III)-catalyzed reductive monoalkylation of electron-rich benzenes with aliphatic carboxylic acids leading to arylalkane derivatives
Moriya, Toshimitsu,Takayama, Kentaro,Konakahara, Takeo,Ogiwara, Yohei,Sakai, Norio
supporting information, p. 2277 - 2281 (2015/03/31)
Described herein is the reaction of electron-rich aromatic compounds with aliphatic carboxylic acids treated with a catalytic amount (5 mol-%) of InI3, 1,1,3,3-tetramethyldisiloxane (TMDS), and molecular iodine. The reductive monoalkylation occurs smoothly to produce the corresponding arylalkane derivatives.
Acceleration of CuI-catalyzed coupling reaction of alkyl halides with aryl Grignard reagents using lithium chloride
Nakata, Kenya,Feng, Chao,Tojo, Toshifumi,Kobayashi, Yuichi
supporting information, p. 5774 - 5777 (2014/12/11)
In the presence of LiCl, CuI-catalyzed coupling reaction of R(alkyl)-X with Ar(aryl)MgBr at rt was completed within 2 h. Effective leaving groups X in R-X were Br, I, OTs, but not Cl. Grignard reagents ArMgBr with both standard and bulky Ar such as 2-MeC
Cation-π interactions in the gas phase methylation of α,ωdiphenylalkanes
Chiavarino, Barbara,Crestoni, Maria E.,Fornarini, Simonetta,Kuck, Dietmar
, p. 4619 - 4624 (2007/10/03)
The methylation of α,ω-diphenylalkanes (C6H5(CH2)nC6H5 , n = 1-6) has been performed in the gas phase using Me2Cl+ ions as alkylating species and toluene as reference substrate. Both in radiolytic experiments at atmospheric pressure and in FT-ICR measurements at 10-8 Torr, the selected diphenylalkanes reacted faster than toluene, the highest reactivity displayed by 1,3-diphenylpropane. The kinetic pattern of the reaction, conforming to the established scheme of an electrophilic alkylation reaction, is consistent with a rate-determining formation of the σ-complex intermediate, at variance with the tert-butylation of the same series of compounds by Me3C+ ions, occurring at the collisional encounter rate. The kinetic features are explained by a marked effect due to the presence of the second aryl ring, providing additional stabilization of both the ion-neutral collision complex and the σ complex with respect to toluene. Both factors contribute to the δEa of ca. 8 kcal mol-1 for the competition of 1,3-diphenylpropane and toluene found in the temperature dependence study of the Me2Cl+ reaction.
The gas-phase reactivity of p-Me3Si-substituted 1,3-diphenylpropane towards charged electrophiles: Intra- and interannular hydrogen migrations
Crestoni, Maria Elisa
, p. 993 - 999 (2007/10/03)
The gas-phase reaction of p-Me3SiC6H4(CH2)3C6H5 (p-TSDPP) with gaseous cations, including C2H5+, Me2Cl+ and DCO+, has been studied in the pressure range from 10-8 to 103 Torr by Fourier-transform ion cyclotron resonance (FT-ICR) and by the radiolytic technique. The protonated or alkylated intermediates undergo intramolecular migration and intermolecular transfer of protons and/or Me3Si+. The results underline the role of the spectator ring in providing internal solvation to an arenium moiety, as evidenced by the noticeable stability towards Me3Si loss with respect to a single-ring model substrate, p-Me3SiC6H4Me (p-TST), upon reaction with the same gaseous ions. The extent of the alkylation route relative to the alkyldesilylation processes, measured as a function of the arenium ion lifetime, permits derivation of the rate constant for the conversion by proton transfer of the originally formed arenium ions to ipso-silylated isomers (k(i)). The estimated values of k(i(p-TST)) = 5 x 109 s-1 and k(i(p-TSDPP)) = 2 x 108 s-1 at 120°C suggest that interannular H shifts are faster than ring-to-ring H transfer, in agreement with previous evidence from tert-butylated arenium ions. The reactivity of [Me3Si=arene]+ adducts, adequately described by the Wheland σ-complex model, does not exclude the intermediacy of an ion-neutral noncovalent complex.
