Copper-catalyzed <i>N</i>-formylation of amines with CO<sub>2</sub> under ambient conditions

Zhang, Suqi; Mei, Qingqing; Liu, Hangyu; Liu, Huizhen; Zhang, Zepeng; Han, Buxing

doi:10.1039/c6ra05199e

Cited by 77 publications

(41 citation statements)

References 36 publications

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“…Whereas the N‐formylation of amines with CO 2 may be achieved by using hydrogen as the reducing agent, harsh reaction conditions and poor functional group tolerance have led to the employment of other reducing agents such as hydrosilanes (Scheme a) . The N‐formylation of amines with hydrosilanes has been achieved with transition‐metal‐based catalysts (e.g., copper and iron) and a number of organocatalysts …”

Section: Methodsmentioning

confidence: 99%

Carbon Dioxide Based N‐Formylation of Amines Catalyzed by Fluoride and Hydroxide Anions

et al. 2016

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We described herein a simple approach for N‐formylation with CO2 and hydrosilane reducing agents. Fluoride and hydroxide salts efficiently catalyzed the reaction, principally through activation of the hydrosilanes, which led to hydrosilane reactivities comparable to those of NaBH4/LiAlH4. Consequently, the N‐formylation of amines with CO2 could be achieved at room temperature and atmospheric pressure. The mechanism of these anionic catalysts contrasts that of the currently reported systems, for which activation of CO2 is the key mechanistic step. Using tetrabutylammonium fluoride as a simple ammonium salt catalyst, the N‐formylated products of both aliphatic and aromatic amines could be obtained in excellent yields with high selectivities.

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Section: Methodsmentioning

confidence: 99%

Carbon Dioxide Based N‐Formylation of Amines Catalyzed by Fluoride and Hydroxide Anions

et al. 2016

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“…[28] Both the simple Zn(salen) and DVB@IL could catalyzet he N-formylation reaction at 40 8Ca nd 1.0 MPa. [29] Therefore, the formation of highly active Zn-H speciesw as beneficial to the activation of SiÀHb ond within hydrosilanes, thereby resulting in the insertion of the CO 2 molecule. [17b] Interestingly,t he POP-based catalyst DVB@ISZ exhibited excellent activity,a nd the 99 %y ield of N-methyl formanilide was obtained under identicalc onditions (Table 3, entry 5).…”

Section: N-formylation Of Amines With Co 2 and Phsihmentioning

confidence: 99%

Metallosalen‐Based Ionic Porous Polymers as Bifunctional Catalysts for the Conversion of CO₂ into Valuable Chemicals

Luo

Chen

et al. 2017

ChemSusChem

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A series of new metallosalen-based ionic porous organic polymers (POPs) were synthesized for the first time using a simple unique strategy based on the free-radical copolymerization reaction. Various techniques were used to characterize the physicochemical properties of these catalysts. These well-designed materials endowed high surface area, hierarchical porous structures, and enhanced CO /N adsorptive selectivity. Moreover, these POPs having both metal centers (Lewis acid) and ionic units (nucleophile) could serve as bifunctional catalysts in the catalytic conversion of CO into high value-added chemicals without any additional co-catalyst under mild and solvent-free conditions, for example, CO /epoxides cycloaddition and Nformylation of amines from CO and hydrosilanes. The results demonstrated that the irregular porous structure was very favorable for the diffusion of substrates and products, and the microporous structural property resulted in the enrichment of CO near the catalytic centers in the CO -involved transformations. Additionally, the superhydrophobic property could not only enhance the chemoselectivity of products but also promote the stability and recyclability of catalysts.

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“…This reactivity has been further exploited in a 'diagonal' approach to CO 2 reduction/ functionalisation, for example in the use of CO 2 as the C1 source for amine N-methylation. 3,37,[44][45][46][47][48][49][50][51][52][53][54] High oxidation state transition metal oxo complexes 55 have been studied in CO 2 reduction chemistry and have been shown to react to form metal carbonates where, in the case of molybdate, the resulting carbonate undergoes hydrosilylation to formate and silylated molybdate, albeit stoichiometrically. [56][57][58][59] Furthermore, rheniumĲV) mono and dioxo complexes act as catalysts for the hydrosilylation of organic carbonyls, [60][61][62][63][64][65] but this activity is not generally seen for the parent perrhenate, ReO 4…”

Section: Introductionmentioning

confidence: 99%

Reduction of carbon dioxide and organic carbonyls by hydrosilanes catalysed by the perrhenate anion

Morris

Weetman

Wennmacher

et al. 2017

Catal. Sci. Technol.

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aThe simple perrhenate salt [NĲhexyl) 4 ]ĳ(ReO 4 )] acts as a catalyst for the reduction of organic carbonyls and carbon dioxide by primary and secondary hydrosilanes. In the case of CO 2 , this results in the formation of methanol equivalents via silylformate and silylacetal intermediates. Furthermore, the addition of alkylamines to the reaction mixture favours catalytic amine N-methylation over methanol production under certain conditions. DFT analysis of the mechanism of CO 2 reduction shows that the perrhenate anion activates the silylhydride forming a hypervalent silicate transition state such that the CO 2 can directly cleave a Si-H bond. IntroductionThe hydrosilylation of CO 2 to silylformates and silylethers is an attractive route for CO 2 utilisation as, unlike hydrogenation, this reaction is exergonic due to the comparative ease of Si-H bond activation and the strength of the Si-O bond, and the availability of relatively inexpensive and environmentally benign hydrosilanes. 66 Important to this chemistry is the formation of a lipophilic ion pair in which electrostatic and hydrogen-bonding interactions are enhanced in the hydrophobic phase. This catalyst has the advantages of ease of synthesis and manipulation and lack of air-sensitivity, and the recovery of the precious metal is driven by straightforward reverse phase-transfer. Given the efficacy of this new catalyst system and the use of high oxidation state rhenium oxo complexes in reduction catalysis, it is shown here that perrhenate can act as a catalyst for the reduction of carbon dioxide to methanol equivalents by hydrosilanes, that the methylation of alkylamines using CO 2 as the C 1 source occurs under similar catalytic conditions, and that this method can be used to reduce aldehydes and ketones to silylalcohols. Results and discussion Reduction of carbon dioxideInitially, the reaction between CO 2 (2.5 bar), PhSiH 3 (2.0 mmol), and pyridinium perrhenate 1 (2.0 mol%) at 80°C in C 6 D 6 in a Teflon-tapped NMR tube was monitored by 1 H NMR spectroscopy. However, only 15% consumption of hydrosilane is seen under these conditions after 16 h ( Fig. S2 and S3, ESI †). In contrast, when the reaction is carried out using the simple lipophilic quaternary ammonium salt [NĲhexyl) 4 ]ĳReO 4 ] 2 (2.5 mol%) with PhSiH 3 in C 6 D 6 at 1 bar of

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Copper-catalyzed N-formylation of amines with CO₂ under ambient conditions

Abstract: N-Formylation of amines with CO2 and PhSiH3 catalyzed by a copper complex.

Cited by 77 publications

References 36 publications

Carbon Dioxide Based N‐Formylation of Amines Catalyzed by Fluoride and Hydroxide Anions

Carbon Dioxide Based N‐Formylation of Amines Catalyzed by Fluoride and Hydroxide Anions

Metallosalen‐Based Ionic Porous Polymers as Bifunctional Catalysts for the Conversion of CO₂ into Valuable Chemicals

Reduction of carbon dioxide and organic carbonyls by hydrosilanes catalysed by the perrhenate anion

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Copper-catalyzed N-formylation of amines with CO2 under ambient conditions

Abstract: N-Formylation of amines with CO2 and PhSiH3 catalyzed by a copper complex.

Cited by 77 publications

References 36 publications

Carbon Dioxide Based N‐Formylation of Amines Catalyzed by Fluoride and Hydroxide Anions

Carbon Dioxide Based N‐Formylation of Amines Catalyzed by Fluoride and Hydroxide Anions

Metallosalen‐Based Ionic Porous Polymers as Bifunctional Catalysts for the Conversion of CO2 into Valuable Chemicals

Reduction of carbon dioxide and organic carbonyls by hydrosilanes catalysed by the perrhenate anion

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Copper-catalyzed N-formylation of amines with CO₂ under ambient conditions

Metallosalen‐Based Ionic Porous Polymers as Bifunctional Catalysts for the Conversion of CO₂ into Valuable Chemicals