Graphene oxide: an efficient and reusable carbocatalyst for aza-Michael addition of amines to activated alkenes

Verma, Sanny; Mungse, Harshal P.; Kumar, Neeraj; Choudhary, Shivani; Jain, Suman L.; Sain, Bir; Khatri, Om P.

doi:10.1039/c1cc15230k

Cited by 270 publications

(147 citation statements)

References 34 publications

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“…Therefore, the catalytic activity was not derived from metal contamination. When other carbon materials, such as commercially available multi-wall carbon nanotubes, graphene, graphite and activated carbon, were employed in the reaction, the results were less desirable than that obtained using C-0 as a catalyst (entries [25][26][27][28][29]. Therefore, the catalytic activity of our catalyst is unique for the alcohol amination reactions.…”

Section: Resultsmentioning

confidence: 96%

“…The FT-IR adsorption peaks of multiwall carbon nanotubes, graphene, graphite and activated carbon were weak at 1,570 cm À 1 , which might explain their low activities ( Supplementary Fig. 2 and Table 1, entries [25][26][27][28][29]. It should be mentioned that a high surface area may be important to achieve high activity as well.…”

Section: Resultsmentioning

confidence: 99%

“…These reactions encompass the oxidative hydrogen atom transfer reactions. In addition, the O-rich carbon materials have been active catalysts in various reactions (that is, nucleophilic addition of alcohol to an epoxide 22 , aldehyde acetalization or esterification 23,24 , Michael addition reactions 25,26 , F-C addition of indoles to a,bunsaturated ketones 27 and synthesis of dipyrromethane 28 , among others 29,30 ). In these studies, nearly all of the organic transformations have been focused on oxidative hydrogen atom transfer reactions or acid-catalysed reactions with heteroatommodified carbon materials (Fig.…”

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confidence: 99%

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Carbon-catalysed reductive hydrogen atom transfer reactions

et al. 2015

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Generally, transition metal catalysts are essential for the reductive hydrogen atom transfer reaction, which is also known as the transfer hydrogenation reaction or the borrowinghydrogen reaction. It has been reported that graphene can be an active catalyst in ethylene and nitrobenzene reductions, but no report has described carbon-based materials as catalysts for alcohol amination via the borrowing-hydrogen reaction mechanism. Here we show the results from the preparation, characterization and catalytic performance investigation of carbon catalysts in transition metal-free borrowing-hydrogen reactions using alcohol amination and nitro compound/ketone reduction as model reactions. XPS, XRD, SEM, FT-IR and N 2 adsorption-desorption studies revealed that C ¼ O group in the carbon catalysts may be a possible catalytically active site, and high surface area is important for gaining high activity. The activity of the carbon catalyst remained unchanged after reuse. This study provides an attractive and useful methodology for a wider range of applications.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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Carbon-catalysed reductive hydrogen atom transfer reactions

et al. 2015

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“…First, the presence of oxygencontaining functional groups allows GO to function as an oxidant for the oxidation of sulphides, 16 olefins and various hydrocarbons 17 . In addition, the acidic nature of GO allows GO to act as a solid acid for hydration, 18 Friedel-Crafts reaction, 19 Aza-Michael additions, 20 condensation 21 and ringopening polymerization 22 . Therefore, it is attractive to develop GO-based carbocatalysts as an alternative to dwindling precious metal resources 6,23 .…”

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confidence: 99%

Probing the catalytic activity of porous graphene oxide and the origin of this behaviour

et al. 2012

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Graphene oxide, a two-dimensional aromatic scaffold decorated by oxygen-containing functional groups, possesses rich chemical properties and may present a green alternative to precious metal catalysts. Graphene oxide-based carbocatalysis has recently been demonstrated for aerobic oxidative reactions. However, its widespread application is hindered by the need for high catalyst loadings. Here we report a simple chemical treatment that can create and enlarge the defects in graphene oxide and impart on it enhanced catalytic activities for the oxidative coupling of amines to imines (up to 98% yield at 5 wt% catalyst loading, under solvent-free, open-air conditions). This study examines the origin of the enhanced catalytic activity, which can be linked to the synergistic effect of carboxylic acid groups and unpaired electrons at the edge defects. The discovery of a simple chemical processing step to synthesize highly active graphene oxide allows the premise of industrial-scale carbocatalysis to be explored.

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“…66 The catalyst was found to be easily recoverable and recyclable with the consistent catalytic activity. Notably, most of these reactions turned out to be productive within shorter reaction time (5-10 min).…”

Section: Aza-michael Addition Reactionmentioning

confidence: 94%