20329-91-3Relevant academic research and scientific papers
Organocalcium-mediated nucleophilic alkylation of benzene
Wilson, Andrew S. S.,Hill, Michael S.,Mahon, Mary F.,Dinoi, Chiara,Maron, Laurent
, p. 1168 - 1171 (2017/12/08)
The electrophilic aromatic substitution of a C–H bond of benzene is one of the archetypal transformations of organic chemistry. In contrast, the electron-rich p-system of benzene is highly resistant to reactions with electron-rich and negatively charged organic nucleophiles. Here, we report that this previously insurmountable electronic repulsion may be overcome through the use of sufficiently potent organocalcium nucleophiles. Calcium n-alkyl derivatives—synthesized by reaction of ethene, but-1-ene, and hex-1-ene with a dimeric calcium hydride—react with protio and deutero benzene at 60°C through nucleophilic substitution of an aromatic C–D/H bond. These reactions produce the n-alkyl benzenes with regeneration of the calcium hydride. Density functional theory calculations implicate an unstabilized Meisenheimer complex in the C–H activation transition state.
Iron-catalyzed allylic arylation of olefins via C(sp3)-H activation under mild conditions
Sekine, Masaki,Ilies, Laurean,Nakamura, Eiichi
supporting information, p. 714 - 717 (2013/04/10)
An aryl Grignard reagent in the presence of mesityl iodide converts an allylic C-H bond of a cycloalkene or an allylbenzene derivative into a C-C bond in the presence of a catalytic amount of Fe(acac)3 and a diphosphine ligand at 0 C. The stereo- and regioselectivity of the reaction, together with deuterium labeling experiments, suggest that C-H bond activation is the slow step in the catalytic cycle preceding the formation of an allyliron intermediate.
Synthesis of Some Deuterated Aromatic Mesomorphic Compounds Used in Broad-Line 2H-NMR Studies
Neubert, Mary E.
, p. 327 - 374 (2007/10/02)
Twenty-one deuterated mesogens of the following types: HOAB (perdeuterated chains), 4-alkoxybenzoic acids (perdeuterated chain and acid deuteron), 7S5 and 8S5 (perdeuterated alkoxy chain), 4-alkoxybenzylidene-4'-alkylanilines (2 or 4 deuterons in the aniline ring, 2-α-deuterons on the alkyl chain and perdeuterated alkyl or alkoxy chain) and TBBA (perdeuterated alkyl chains or anil deuterons) were prepared for use in broad-line 2H-NMR by using standard literature methods.The required 4-alkoxybenzoic acids, aldehydes and anilines with perdeuterated chains were prepared by alkylation of the appropriate 4-substituted phenol.The acid proton in the 4-alkoxybenzoic acids were replaced with a deuteron either by basic hydrolysis of the ester or acid chloride or by base-catalyzed exchange on the acid.Two deuterons were incorporated into the aniline ring ortho to the amino group by exchange in dilute H2SO4.Four ring deuterons, two α-chain deuterons or a perdeuterated chain were incorporated into 4-alkylanilines by the following sequence of steps: Friedel-Crafts acylation of benzene with an acid chloride, catalytic reduction, Friedel-Crafts acylation with oxalyl chloride, hydrolysis in base and a Schmidt rearrangement in H2SO4.New deuteration equipment was designed for the catalytic reduction using deuterium.IR NMR and MS were used to determine the deuterium content of these compounds.Small differences in mesophase transition temperatures were observed for mesogens containing perdeuterated alkyl or alkoxy chains.
Arene-Metal Complexes. 12. Reaction of (η6-Benzene)tricarbonylchromium with n-Butyllithium
Card, Roger J.,Trahanovsky, Walter S.
, p. 2555 - 2559 (2007/10/02)
The reaction of (η6-benzene)tricarbonylchromium with n-butyllithium in tetrahydrofuran at -20 deg C results in the formation of an intermediate which may be quenched by the addition of methyl iodide or iodine to yield (toluene)tricarbonylchromium or (iodobenzene)tricarbonylchromium in 50 or 26percent yield,respectively.The chemistry and the 1H NMR spectrum of this intermediate are consistent with its assignment as (η6-phenyllithium)tricarbonylchromium.If this intermediate is allowed to warm to 0 deg C in the presence of an excess of n-butyllithium,n-butylbenzene is obtained in 80percent yield.Mechanistic details are discussed.
