Copper nanoparticles supported on silica coated maghemite as versatile, magnetically recoverable and reusable catalyst for alkyne coupling and cycloaddition reactions

Nador, Fabiana; Volpe, María Alicia; Alonso, Francisco; Feldhoff, Armin; Kirschning, Andreas; Radivoy, Gabriel

doi:10.1016/j.apcata.2013.01.023

Cited by 146 publications

(74 citation statements)

References 43 publications

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“…30 TEM revealed the presence of spherical nanoparticles, with an average particle size of 3.0 ± 0.8 nm, well dispersed on the magnetic support (Figure 4). The CuNPs/MagSilica catalyst manifested a good performance in the three-component CuAAC from organic halides, using 4.3 mol% Cu in water at 70 ºC.…”

Section: Multicomponent Synthesis Of 123-triazoles From Organic Halmentioning

confidence: 99%

Copper Nanoparticles in Click Chemistry

2015

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2The challenges of the 21 st century demand scientific and technological achievements which must be developed under sustainable and environmentally benign practices. In this vein, Click Chemistry and Green Chemistry walk hand in hand on a pathway of rigorous principles which help to safeguard the health of our planet against negligent and uncontrolled production. The copper-catalyzed azide-alkyne cycloaddition (CuAAC), the paradigm of a click reaction, is one of the most reliable and widespread synthetic transformations in organic chemistry, with multidisciplinary applications. Nanocatalysis is a Green Chemistry tool which can increase the inherent effectiveness of the CuAAC because of the enhanced catalytic activity of nanostructured metals and their plausible reutilization capability as heterogeneous catalysts.In this account, our contribution to Click Chemistry is described using unsupported and supported copper nanoparticles (CuNPs) as catalysts prepared by chemical reduction. Cu(0)NPs (3.0 ± 1.5 nm) in tetrahydrofuran were found to catalyze the reaction of terminal alkynes and organic azides, in the presence of triethylamine, at rates comparable to those achieved under microwave heating (10-30 min in most cases). Unfortunately, the CuNPs underwent dissolution under the reaction conditions and, consequently, could not be recovered. Compelling experimental evidence on the in-situ generation of highly reactive copper(I) chloride and the participation of copper(I) acetylides was provided.The supported CuNPs were found to be more robust and efficient catalyst than the unsupported counterpart in the following terms: (a) the multicomponent variant of the CuAAC could be applied, (b) with substantial decrease in the metal loading, (c) reactions could be conducted in neat water, and (d) with easy recovery and reutilization of the catalyst. In particular, the catalyst composed of oxidized CuNPs/C (Cu 2 O/CuO, 6.0 ± 2.0 nm) was shown to be highly versatile and 3 very effective in the multicomponent and regioselective synthesis of 1,4-disubstituted-1,2,3-triazoles in water from organic halides as azido precursors; magnetically recoverable CuNPs (3.0 ± 0.8 nm)/MagSilica could be alternatively used for the same purpose under similar conditions. Incorporation of an aromatic substituent at the position 1 of the triazole could be accomplished using the same CuNPs/C catalytic system, but starting from aryl diazonium salts or anilines as azido precursors. CuNPs/C in water also catalyzed the regioselective double-click synthesis ofhydroxy-1,2,3-triazoles from epoxides. Furthermore, alkenes could be also used as azido precursors through a one-pot CuNPs/C-catalyzed azidosulfenylation-CuAAC sequential protocol, providing -methylsulfanyl-1,2,3-triazoles in a stereo-and regioselective manner. In all the types of reaction studied, CuNPs/C exhibited better behavior than some commercial copper catalysts as regards the metal loading, reaction time, yield and recyclability. Therefore, the results of this study also highlight the utility ...

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Section: Multicomponent Synthesis Of 123-triazoles From Organic Halmentioning

confidence: 99%

Copper Nanoparticles in Click Chemistry

2015

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“…30b) [153]. Other recently reported nanostructured Cu catalysts for three-component CuAAC reactions included CuNPs [154], heterogeneous porous Cu(0) [155], and CuNPs on silica coated maghemite nanoparticles (CuNPs/mag silica) [156]. Since Lipshutz's seminal study involving nickel oxide NPs in the CuAAC reaction [157], essentially Cu-M bimetallic alloys (M = metal or its oxides NPs, mainly Fe and Ni) have been explored in the AAC reaction.…”

Section: Cuaacmentioning

confidence: 99%

Metal-catalyzed azide-alkyne “click” reactions: Mechanistic overview and recent trends

Changlong

Ikhlef

Kahlal

et al. 2016

Coordination Chemistry Reviews

279

162

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Highlights-The review is focused on the mechanistic aspects and recent trends (since 2012) of the metal-catalyzed azide-alkyne cycloaddition (MAAC) so-called "click" reactions with catalysts based on various metals (Cu, Ru, Ag, Au, Ir, Ni, Zn, Ln), although Cu (I) catalysts are still the most used ones.-These MAAC reactions are by far the most common click reactions relevant to the "green chemistry" concept.-Mechanistic investigations are essential to reaction improvements and subsequent applications, and indeed as shown in this review the proposed mechanisms have been multiple during the last decade based on theoretical computations and experimental search of intermediates.-New trends are also presented here often representing both exciting approaches for various applications and new challenges for further mechanistic investigations.

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“…Most of the examples of multicomponent 1,2,3-triazole syntheses are carried out in water or under neat conditions using heterogeneously supported catalysts like Cu(OAc) 2 on MCM-41, 27 NHC-Cu(I) complexes on silica 28 as well as magnetically recoverable heterogeneous Cu catalysts 29 or copper nanoparticles on silica coated magnetic nanoparticles (5-30 nm). 30 In the above mentioned cases the reaction is carried out in the range of 70-120°C for a few hours in order to achieve high yields. Some alternative systems exist like the employment of mechano-chemical conditions in a ball milling apparatus using a copper vial at high temperature for at least 16 h or the use of a structurally well-defined copper(I) isonitrile complex, 31 insoluble in the reaction medium, that can be readily recovered by precipitation and filtration and recycled for at least five runs without significant loss of activity.…”

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confidence: 99%