Synthesis of α-trifluoromethyl ethanone oximes <i>via</i> the three-component reaction of aryl-substituted ethylenes, <i>tert</i>-butyl nitrite, and the Langlois reagent

Lu, Kui; Wei, Xianfu; Li, Quan; Li, Yuxuan; Ji, Liangshuo; Hua, Erbing; Dai, Yujie; Zhao, Xia

doi:10.1039/c9qo00940j

Cited by 19 publications

(11 citation statements)

References 94 publications

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“…The tautomerism reaction of 3,3,3-trifluoro-1-phenylpropan-1-nitric oxide(IM(5)) to the final product α-trifluoromethylethyl ketoxime(P) is the rate-limiting step (step 6). The substituents on para position of aryl ring and β-C do not influence the reaction rate significantly, which indicates that the reaction has a good adaptability to substrates containing different substituents, which has also been confirmed in experimental studies [45]. Based on our calculation, though the solvent effect does not influence the energy barrier of the tautomerism of step 6 significantly, the existence of water will change the reaction mechanism of step 6 and significantly reduces its energy barrier.…”

Section: Discussionsupporting

confidence: 75%

“…On the other hand, the energy barrier of final step of the reaction in this study is as high as 57.80kcal/mol and the energy barrier of step 1 is 47.42kcal/mol in vacuum, indicating that this reaction should be carried out at a higher temperature, and the high boiling point of DMSO can provide a higher temperature environment to facilitate the reaction. Therefore, the actual reaction is chosen to be carried out in DMSO solvent [45]. .…”

Section: The Effect Of the Different Solvents On The Difunctionalization Reactionmentioning

confidence: 99%

“…Our group previously investigated the bifunctionalization reaction of aryl-substituted ethylene with Langlois reagent (CF 3 SO 2 Na) as trifluoromethylation reagent and tert-butyl nitrite (TBN) as oxidant and oxime source, which introduced a trifluoromethyl and an oxime simultaneously at the double bond position. Based on NMR and isotope tracking experiments, the following putative reaction mechanism was proposed [45] (Scheme 1): Scheme 1. The putative reaction mechanism of simultaneous trifluoromethylation and oximation of substituted styrene.…”

Section: Introductionmentioning

confidence: 99%

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DFT study on the mechanism of simultaneous trifluoromethylation and oximation of aryl-substituted ethylene.

Wang

Meng

et al. 2021

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The effects of different substituents located at the para position of the aromatic ring and β carbon atom of the styrene on the reaction were investigated. The results showed that the reaction steps with higher energy barriers changed a little with the substituents of the reactants, which indicates that the reaction has a good adaptability to reactants containing different substituents. It was found the proton transfer in the final tautomerism step of nitroso intermediate to oxime is the rate limiting step under anhydrous conditions. Although the solvent effect did not influence the the rate limiting step significantly, the water mediated proton transfer significantly decreased the energy barrier of final tautomerism step. Compared with the direct proton transfer in vacuum, the energy barrier of the final tautomerism step decreased from 57.80kcal/mol in vacuum to 12.98kcal/mol with the water mediated proton transfer in water, which declined by 77.5%. When water participates in rate-limiting steps in organic solvents, the energy barrier also decreases significantly, which indicates that a small amount of water in the organic solvent is conducive to the reaction. This study is of great significance for the application of bifunctionalized reaction in the synthesis of organic fluoride compounds with different substituents.

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Section: Discussionsupporting

confidence: 75%

Section: The Effect Of the Different Solvents On The Difunctionalization Reactionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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DFT study on the mechanism of simultaneous trifluoromethylation and oximation of aryl-substituted ethylene.

Wang

Meng

et al. 2021

Preprint

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“…In this three‐component reaction, tert‐butyl nitrite employed not only as an oxidant but also as a source of the oxime (Scheme 23). According to the reported reaction mechanism, trifuoromethyl radical wsa formed by oxidition of CF 3 SO 2 Na, followed by the addition of the radical to alkene to form a carbon‐centred radical which undergoes trapping with nitroxyl radical to afford a β‐CF 3 ‐substituted oximes [65] …”

Section: Application Of Langlois’ Reagent In Organic Transformationsmentioning

confidence: 99%

Recent Advances on the Application of Langlois’ Reagent in Organic Transformations

et al. 2021

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Langlois’ reagent (trifluoromethanesulfinate salt) has been proven to be a valuable reagent for the synthesis of various classes of molecules, mainly trifluoromethylated compounds, in academic, biological and industrial research. Synthetic uses of Langlois’ reagent in organic transformations of aromatic and heteroaromatic compounds, alkenes, alkynes, boronic acids, carboxylic acids, and etc are discussed.This review aims to demonstrate the ongoing utility of Langlois’ reagent in the preparation of various classes of organic compounds. Furthermore, to address the recent collective papers, the current review summarizes and comprehensively describes manuscripts on synthetic applications of Langlois’ reagent since 2015 until today.

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“…Furthermore, sulfinates can also be used to afford organic radicals under oxidative conditions . One significant example for the utility and the versatility of this synthetic approach is the radical trifluoromethylation of organic compounds using sodium trifluoromethanesulfinate (called the Langlois reagent). − Using oxidants such as tert -butyl hydroperoxide or persulfates, • CF 3 radicals are generated under mild conditions, yielding the corresponding trifluoromethylated products in good yields. − …”

Section: Introductionmentioning

confidence: 99%

Chain-End Functionality: The Key Factor toward Fluoropolymer Thermal Stability

et al. 2021

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The aqueous radical homopolymerization of vinylidene fluoride (VDF), as well as its copolymerizations with hexafluoropropylene (HFP) or perfluoromethyl vinyl ether (PMVE), and its terpolymerization with HFP and PMVE, initiated by trifluoromethyl radicals ( • CF 3 ), generated from the ammonium persulfate (APS) and potassium trifluoromethyl sulfinate (CF 3 SO 2 K) redox system are presented. The optimization of the experimental conditions in terms of initial reactant molar ratios, temperature, and reaction time was achieved. The best results were obtained at 60 °C, in water, without any surfactant, using 0.9 equiv of APS as the oxidant with respect to CF 3 SO 2 K. PVDF, poly(VDF-co-HFP), poly(VDF-co-PMVE), or poly(VDF-ter-PMVE-ter-HFP) copolymers were obtained in high yields (varying between 89 and 100%) and with molar masses up to 113,000 g/mol.The 1 H and 19 F NMR spectroscopies revealed that, under optimized conditions, the formed chain ends were exclusively CF 3 or CF 2 H. The influence of the nature of the chain end on the thermal stability showed that PVDFs terminated by CF 3 were more stable than their analogues bearing sulfate end groups by 120 °C. In addition, the prepared CF 3 -PVDFs had 53% of crystallinity (compared to 47% for PVDF initiated from APS alone), which offers excellent resistance to conventional organic solvents including dimethyl sulfoxide, acetone, and dimethyl formamide.

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Synthesis of α-trifluoromethyl ethanone oximes via the three-component reaction of aryl-substituted ethylenes, tert-butyl nitrite, and the Langlois reagent

Abstract: A three-component reaction of aryl-substituted ethylenes, tert-butyl nitrite, and the Langlois reagent to synthesize a-trifluoromethyl ethanone oximes was developed.

Cited by 19 publications

References 94 publications

DFT study on the mechanism of simultaneous trifluoromethylation and oximation of aryl-substituted ethylene.

DFT study on the mechanism of simultaneous trifluoromethylation and oximation of aryl-substituted ethylene.

Recent Advances on the Application of Langlois’ Reagent in Organic Transformations

Chain-End Functionality: The Key Factor toward Fluoropolymer Thermal Stability

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