Phenol-Directed C–H Functionalization

Huang, Zheng; Lumb, Jean‐Philip

doi:10.1021/acscatal.8b04098

Cited by 197 publications

(147 citation statements)

References 273 publications

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“…Moreover, as mentioned above, it has been reported that the presence of certain reductive intermediates, such as hydroquinone or catechol, play an important role in the Fenton mechanism [77]. Therefore, these intermediates could accelerate the H 2 O 2 decomposition during the oxidation of OII.…”

Section: 222mentioning

confidence: 93%

Natural diatomites: Efficient green catalyst for Fenton-like oxidation of Orange II

Inchaurrondo

Font

Ramos

et al. 2016

Applied Catalysis B: Environmental

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Section: 222mentioning

confidence: 93%

Natural diatomites: Efficient green catalyst for Fenton-like oxidation of Orange II

Inchaurrondo

Font

Ramos

et al. 2016

Applied Catalysis B: Environmental

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“…[147] Dirigierte Alkylierungen von Phenolen gehen oft mit mçglichen viergliedrigen Metallacyclen einher, weshalb die Rolle der Hydroxygruppe als dirigierende Gruppe fraglich ist. Dirigierte C-H-Alkylierungen bieten eine effiziente Alternative,d ie -z umindest teilweise -e inige dieser Einschränkungen umgeht; sie werden in diesem Abschnitt zusammengefasst.…”

Section: Phenole Und Derivate Als Dirigierende Gruppenunclassified

“…Beispiele sind:Dicumyl-oder Di-tert-butylperoxid (mithilfe von Palladiumkatalyse), [186] Carbonsäuren (mithilfe von Palladiumkatalyse) und Cycloalkane (mithilfe von Rutheniumkatalyse), [147] die allerdings in den meisten Fällen Gemische aus mono-und dialkylierten Produkten ergeben;T oluolderivate, die abhängig von dem fürd as Ruthenium verwendeten Liganden zur regioselektiven Einführung von Benzylgruppen in ortho- [187a] oder meta-Position [187a,b] eingesetzt werden kçnnen; sowie a-Carbonylsulfoxonium-Ylide,d ie effizient ein Methylenketon ortho zu verschiedenen dirigierenden Gruppen (Pyridin, Pyrimidin, Chinolin und Pyrazol) in Gegenwart eines Rhodium- [188a,b] oder Cobaltkatalysators [188c] einführen. Beispiele sind:Dicumyl-oder Di-tert-butylperoxid (mithilfe von Palladiumkatalyse), [186] Carbonsäuren (mithilfe von Palladiumkatalyse) und Cycloalkane (mithilfe von Rutheniumkatalyse), [147] die allerdings in den meisten Fällen Gemische aus mono-und dialkylierten Produkten ergeben;T oluolderivate, die abhängig von dem fürd as Ruthenium verwendeten Liganden zur regioselektiven Einführung von Benzylgruppen in ortho- [187a] oder meta-Position [187a,b] eingesetzt werden kçnnen; sowie a-Carbonylsulfoxonium-Ylide,d ie effizient ein Methylenketon ortho zu verschiedenen dirigierenden Gruppen (Pyridin, Pyrimidin, Chinolin und Pyrazol) in Gegenwart eines Rhodium- [188a,b] oder Cobaltkatalysators [188c] einführen.…”

Section: Alkylierung Mit Anderen Reagentienunclassified

Jenseits von Friedel und Crafts: dirigierte Alkylierung von C‐H‐Bindungen in Arenen

Evano

Theunissen

2019

Angewandte Chemie

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Die Alkylierung von Arenen ist eine der grundlegendsten Transformationen in der chemischen Synthese und führt in vielen wissenschaftlichen Bereichen zu privilegierten Molekülgerüsten. Klassische Methoden für die Einführung von Alkylgruppen in Arene beruhen zumeist auf der Friedel‐Crafts‐Reaktion, Radikaladditionen, Metallierungen oder Präfunktionalisierungen von Arenen; die Anwendungsbreite, Effizienz und Selektivität dieser Methoden sind jedoch begrenzt. Außerdem bauen sie auf der inhärenten Reaktivität des Ausgangsarens auf, die die Alkylierung in einer bestimmten Position bevorzugt und die Einführung von Alkylketten an anderen Stellen wesentlich schwieriger macht. Dieses Problem kann durch die Verwendung einer dirigierenden Gruppe angegangen werden, die in Gegenwart eines Metallkatalysators die regioselektive Alkylierung einer C‐H‐Bindung vereinfacht. Diese dirigierten Alkylierungen von C‐H‐Bindungen in Arenen werden im vorliegenden Aufsatz zusammengefasst.

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“…[1][2][3][4][5][6][7][8][9][10][11] To obtain good dispersibility of NPs, the surface of metal NPs are directly modified with organic materials or the NPs are mixed with dispersion media such as fatty acids and amines with long alkyl chains. Owing to the unique surface structure derived from their fine primary particles, the TiO 2 nanoparticle assemblies show excellent dispersion ability of Au nanoparticles on their rough surface.…”

mentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11] To obtain good dispersibility of NPs, the surface of metal NPs are directly modified with organic materials or the NPs are mixed with dispersion media such as fatty acids and amines with long alkyl chains. [1][2][3][4][5][6][7][8][9][10][11] To obtain good dispersibility of NPs, the surface of metal NPs are directly modified with organic materials or the NPs are mixed with dispersion media such as fatty acids and amines with long alkyl chains.…”

mentioning

confidence: 99%

Sintering‐Resistant Metal Catalysts Supported on Concave‐Convex Surface of TiO₂ Nanoparticle Assemblies

et al. 2018

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We herein describe a novel use of spherical nanoparticle assemblies of TiO 2 with ultrafine surface concave-convex structure as a catalyst support to prevent the sintering of dispersed metal nanoparticles. Owing to the unique surface structure derived from their fine primary particles, the TiO 2 nanoparticle assemblies show excellent dispersion ability of Au nanoparticles on their rough surface. Extremely exothermic CO oxidation as a probe reaction confirmed the high catalytic activity and stability of Au nanoparticles on the TiO 2 support and sintering resistance even after several cycles of the heat stress reaction at high temperatures.Well-dispersed metal nanoparticles (NPs) have received much attention in many fields of chemistry, physics, materials science, and practical applications, including synthetic chemistry, energy conversion, and environmental issues. [1][2][3][4][5][6][7][8][9][10][11] To obtain good dispersibility of NPs, the surface of metal NPs are directly modified with organic materials or the NPs are mixed with dispersion media such as fatty acids and amines with long alkyl chains. [12][13][14] In the case of heterogeneous catalysts, the dispersion media are called "supports." [15][16][17][18][19][20][21] Metal oxides are the most commonly used supports, because they not only have high heat tolerance and mechanical strength required for very high temperatureÀhigh pressure reactions, but also provide a wide surface area for dilution effect to occur that releases reaction heat. It is also believed that the metal oxide surface affords electronic effect on their catalytic activity of supported metal NPs.In the case of exothermic catalytic reactions, the temperature of catalysts, especially that of the catalyst surface, becomes notably high. Under such high temperature condi-tions, one of the most serious problems is catalyst sintering, because of which several catalyst NPs agglomerate to form large particles. This reduces the activity of catalyst NPs because of the loss of the surface area. [22][23][24][25][26] Ablation of the NPs from the support surface, called leaching, is another common problem that shortens the catalyst life-time. Generally, once the catalyst NPs are sintered or leached, they do not reproduce the original size, morphology, surface area, and crystal structure. Thus, it is better to focus on the prevention of sintering and leaching rather than to regenerate the NPs.To prevent the sintering and leaching of metal NPs, several methods such as alloying, ligand-assisted pinning, fixing on defects, and encapsulating as core-shell/sheath structures by oxides or polymer have been reported. [27][28][29][30][31][32][33][34][35][36][37] These strategies mainly focus on the isolation of the individual nanocatalyst, resulting in low possibility of catalyst aggregation/growth. However, some of them reduce the accessibility of the reactant to the active sites of the catalyst NPs, which lead to a lowering in their reaction rate. Besides, most of their preparation methods are usually complicate...

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Phenol-Directed C–H Functionalization

Cited by 197 publications

References 273 publications

Natural diatomites: Efficient green catalyst for Fenton-like oxidation of Orange II

Natural diatomites: Efficient green catalyst for Fenton-like oxidation of Orange II

Jenseits von Friedel und Crafts: dirigierte Alkylierung von C‐H‐Bindungen in Arenen

Sintering‐Resistant Metal Catalysts Supported on Concave‐Convex Surface of TiO₂ Nanoparticle Assemblies

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Phenol-Directed C–H Functionalization

Cited by 197 publications

References 273 publications

Natural diatomites: Efficient green catalyst for Fenton-like oxidation of Orange II

Natural diatomites: Efficient green catalyst for Fenton-like oxidation of Orange II

Jenseits von Friedel und Crafts: dirigierte Alkylierung von C‐H‐Bindungen in Arenen

Sintering‐Resistant Metal Catalysts Supported on Concave‐Convex Surface of TiO2 Nanoparticle Assemblies

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Product

Resources

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Sintering‐Resistant Metal Catalysts Supported on Concave‐Convex Surface of TiO₂ Nanoparticle Assemblies