NMR spectra of F19 in trifluorostyrenes

Sergeev, N. M.; Shapet'ko, N. N.; Timofeyuk, G. V.

doi:10.1007/bf00745954

Cited by 3 publications

(3 citation statements)

References 3 publications

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“…But the coupling reaction in the absence of TMEDA (from the zinc reagent generated in THF medium) produced exclusively (99% by 19 F NMR) the styrene 2 with no addition−elimination product formation (Table ). Isolation of the product by column chromatography produced 64% yield of pure 2 …”

Section: Resultsmentioning

confidence: 99%

Room Temperature Preparation of Trifluoroethenylzinc Reagent by Metalation of the Readily Available Halocarbon HFC-134a and an Efficient, Economically Viable Synthesis of 1,2,2-Trifluorostyrenes

Raghavanpillai

Burton

2004

J. Org. Chem.

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Trifluoroethenylzinc reagent [CF(2)=CFZnX] was generated from the readily available halocarbon HFC-134a by an in situ metalation-transmetalation procedure at temperatures near to room temperature (15-20 degrees C). By systematic standardization of the metalation experiments by manipulation of solvent, cosolvent, temperature, zinc salt, and the base, the trifluoroethenylzinc reagent was produced in 73% yield at 20 degrees C in THF medium. The palladium-catalyzed cross-coupling reaction of the trifluoroethenylzinc reagent with various aryl iodides was carried out under mild reaction conditions to produce 1,2,2-trifluorostyrenes in 59-86% isolated yields. The stability of the intermediate trifluoroethenyllithium reagent was compared at different temperatures and solvent systems. Experimental evidence for the mono-anion from HFC-134a (CF(3)CHF(-)) was obtained by the trapping of the mono-anion with zinc halide in THF/TMEDA medium. The structure and complexation of both the mono- and bis-trifluoroethenylzinc reagents with TMEDA and other ligands are discussed.

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Section: Resultsmentioning

confidence: 99%

Room Temperature Preparation of Trifluoroethenylzinc Reagent by Metalation of the Readily Available Halocarbon HFC-134a and an Efficient, Economically Viable Synthesis of 1,2,2-Trifluorostyrenes

Raghavanpillai

Burton

2004

J. Org. Chem.

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“…The interpretation of the 13C and 19F NMR spectra of Z-and E-I~-X-substituted r (X = F (1), CI (2), CpFe(CO) 2 (3), Re(CO) 5 (4), Re2(CO)gNa (5)) required reliable and justified assignment of signals to particular (et or 13) fluorine or carbon atoms at the double bond. Another problem was to prove the structures of fluoro-derivatives, containing only one fluorine atom, for example, Z-PhCF=CCIFe(CO)2C p (6). At present, the commonest and the most direct method for solving these problems is heteronuclear correlation spectroscopy.…”

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confidence: 99%

“…do not appear quite reliable, in particular, because the signal assignment was not sufficiently substantiated. Calculation of the chemical shift of fluorine in Z-PhCF=CCIFe(CO)2CP (6) Table 1). Nevertheless, the Z-and E-configurations of compounds 3--5 can be identified quite reliably using the rule for the spin-spin coupling constants 3dF, Fe/s << ]JF,Ftra,t,, from which no, exceptions have been observed so far.…”

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confidence: 99%

13C and19F NMR study of α,β-difluorostyryl derivatives of transition metal carbonylates. A method of signal assignment based on the carbon—fluorine spin-spin coupling constants

et al. 1998

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The f3C and 19F NMR spectra of Z-and E-isomers ofl~-X-substituted cq[3-difluorostyrenes (X = F, CI, CpFe(CO) 2, Re(CO)s, Re2(CO)gNa) were studied. Direct and long-range (across I--5 bonds) spin-spin coupling constants and the (13C--12C) isotope shifts in the I~ NMR spectra were determined. The study of the 13C satellites in the tgF NMR spectra of substituted difluorostyrenes permitted assignment of the t3C NMR signals of the vinylic carbon atoms. Similarly, the signals in 19F NMR spectra were assigned based on coupling constants of fluorine with ipso-earbon. These assignments were found to be in good agreement with the data available from the literature (X = F, CI). The developed approach was applied to the elucidation of the structure of Z-PhCF=CCIFe(CO)~Cp.

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Physico-chemical study of ionic equilibria for poly-2 and poly-4-vinylpyridines in alcohol-water solutions

Kirsh

Komarova

Луковкин

1973

European Polymer Journal

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NMR spectra of F19 in trifluorostyrenes

Cited by 3 publications

References 3 publications

Room Temperature Preparation of Trifluoroethenylzinc Reagent by Metalation of the Readily Available Halocarbon HFC-134a and an Efficient, Economically Viable Synthesis of 1,2,2-Trifluorostyrenes

Room Temperature Preparation of Trifluoroethenylzinc Reagent by Metalation of the Readily Available Halocarbon HFC-134a and an Efficient, Economically Viable Synthesis of 1,2,2-Trifluorostyrenes

13C and19F NMR study of α,β-difluorostyryl derivatives of transition metal carbonylates. A method of signal assignment based on the carbon—fluorine spin-spin coupling constants

Physico-chemical study of ionic equilibria for poly-2 and poly-4-vinylpyridines in alcohol-water solutions

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