6962-10-3Relevant academic research and scientific papers
Zeolite catalyzed hydroarylation of alkenes with aromatic amines under organic ligand-free conditions
Li, Teng,Liu, Shujuan,Shi, Feng,Wang, Hongli,Wang, Xinzhi,Yuan, Hangkong,Zhao, Kang
, p. 18 - 29 (2021/01/12)
The hydroarylation of alkenes with aromatic amines is recognized as the most atom-economical and straightforward approach to obtain functional aromatic amines, which are versatile building blocks in organic synthesis and material chemistry. However, controllable synthesis of single hydroarylation product is still a significant challenge because hydroarylation reaction often delivers four hydroarylation products and hydroamination products are also produced during the reaction. Herein, we report the first example of heterogeneous zeolite catalyzed hydroarylation of styrene and norbornene with aniline derivatives under organic ligand-free conditions. With the USY zeolite as catalyst, a wide scope of alkenes and aromatic amines with various functional groups are smoothly converted into the corresponding products in 48–95% yields with high regioselectivity. Detailed characterizations revealed that Lewis acid can promote Hofmann-Martius rearrangement of hydroamination products toward hydroarylation products, resulting in high selectivity for hydroarylation products. In addition, it could be found that the weak acid sites of zeolite play a key role in forming hydroarylation products. Furthermore, the catalyst can be reused at least 10 times without obvious deactivation. This work may promote the development of heterogeneous catalyst system for alkene hydroarylation.
Hydroarylation of Alkenes Using Anilines in Hexafluoroisopropanol
Colomer, Ignacio
, p. 6023 - 6029 (2020/07/21)
Providing new methods for the selective functionalization of small molecules is highly desirable, because installing molecular diversity in a desired position, for example, allows one to modulate bioactive molecules. This work reports a method for the selective functionalization of anilines using hexafluoroisopropanol (HFIP) as a solvent to promote an acid-catalyzed hydroarylation of olefins. Mechanistic experiments revealed that HFIP both protonates the alkene and selectively enables anilines toward the electrophilic aromatic substitution. This powerful strategy has been applied to the functionalization of the anti-inflammatory mefenamic acid with chemocontrol and regiocontrol.
Scandium-Catalyzed para-Selective Alkylation of Aromatic Amines with Alkenes
Su, Jianhong,Cai, Yanping,Xu, Xin
supporting information, p. 9055 - 9059 (2019/11/11)
An efficient para-alkylation of primary and secondary anilines with a variety of sterically encumbered alkenes using a simple β-diketiminato scandium catalyst is reported. This protocol features 100% atom economy, excellent chemo- and regioselectivity, broad substrate scope, and good functional group tolerance. Mechanistic studies disclosed that the reaction probably proceeded via a tandem hydroamination/Hofmann-Martius rearrangement.
Application of scandium-containing rare earth catalyst in catalysis of aromatic amine para-alkylation reaction
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Paragraph 0171-0177, (2019/07/04)
The invention relates to an application of a scandium-containing rare earth catalyst in catalysis of aromatic amine para-selective alkylation reaction. The structural formula of the scandium-containing rare earth catalyst is shown in the specification. The aromatic amine is aromatic primary amine or aromatic secondary amine. The invention also discloses a preparation method of the para-alkylated aromatic amine. The preparation method comprises the following steps: performing a reaction on aromatic amine shown in the formula (1) and olefin shown in the formula (2) in an organic solvent at 60-150 DEG C under the catalytic action of a scandium-containing rare earth catalyst to obtain the para-alkylated aromatic amine, the reaction route being represented as the specification; wherein R1 is hydrogen, an aryl group or a C1-C10 alkyl group; R2 is hydrogen, C1-C4 alkyl group, C1-C4 alkoxy group, aryl group or halogen and cannot be substituted at a para-position; X is methylene or sulfur atom,and n1 is any one of 0 to 4; R3 is C1-C20 alkyl group, aryl group or cyclized with R5 through a plurality of methylene groups, and the number n2 of the methylene groups is any one of 1 to 4; R4 is hydrogen, C1-C20 alkyl group, aryl group, thienyl group, benzofuryl group or substituted aryl group; R5 is hydrogen, methyl or methylene; R6 is hydrogen.
Comparison between SiMe2 and CMe2 spacers as σ-bridges for photoinduced charge transfer
Van Walree, Cornelis A.,Roest, Martin R.,Schuddeboom, Wouter,Jenneskens, Leonardus W.,Verhoeven, Jan W.,Warman, John M.,Kooijman, Huub,Spek, Anthony L.
, p. 8395 - 8407 (2007/10/03)
The potential of dimethylsilylene and isopropylidene σ-spacers as bridges for photoinduced charge transfer (CT) in 4-cyano-4'-(dimethylamino)- and 4-cyano-4'-methoxy-substituted diphenyldimethylsilanes and 2,2-diphenylpropanes was studied. Fluorescence solvatochromism and time-resolved microwave conductivity measurements show that upon photoexcitation a charge separated state (D.+σA.-)* is populated in all compounds. Excited state dipole moments for a given donor-acceptor combination are, irrespective of the bridge, equal. The CT states of the silanes are however lying at lower energies, implying that the presence of silicon thermodynamically facilitates the CT process. Cyclic voltammetry data of model compounds show that this is a consequence of the lowering of the acceptor reduction potential by the silicon bridge. It was however inferred from radiative decay rates that the electronic coupling between the CT and locally excited states as well as the coupling between the ground and CT state is larger for the carbon-bridged compounds. As shown by both solution and solid state electronic spectra and radiative decay rates, the photophysics of the DσA compounds are dominated by intensity borrowing of the CT transitions from transitions localized in the Dσ and σA chromophores.
Alkylation and aralkylation of aromatic amines
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, (2008/06/13)
Compounds having the formula I STR1 as well as salts or metal salt complexes thereof, in which formula I n, R1, R2 and Z have the meanings given in claim 1, can be prepared under mild reaction conditions by reacting 1.0 mole of an ar
