Trifluoroacetonitrile N-oxide

Del'tsova, D. P.; Ananyan, É. S.; Gambaryan, N. P.

doi:10.1007/bf00869028

Cited by 4 publications

(5 citation statements)

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“…Bimolecular loss routes to the furoxan are, as noted in the next section, much more favored. The higher energy species, oxazirine (6) and the two other minima 5 and 7, are in much shallower wells. Fulminate (5) isomerizes with a barrier (TS 10) of 28.5 kcal/mol into the thermodynamically more stable 4.…”

Section: Resultsmentioning

confidence: 95%

“…[6][7][8][9][10][11][12] Recently, 1 has proven to be of interest in medical applications, acting as a reagent for preparing tachykinin receptor antagonists 13 as well as in the production of herbicides, pesticides, and insecticides. 14 In most cases, 1 is generated as a reactive dipolarophile in solution from Br-or Cl-oximes, specifically trifluoroacetohydroximoyl bromide and chloride, respectively, since it has been stated 6 to be unstable in solution "even at a temperature below -20°".…”

Section: Introductionmentioning

confidence: 99%

“…Trifluoroacetonitrile N-oxide, CF 3 CNO (1), is often used in [2 + 3] cycloaddition reactions where five-membered heterocycles, for example, oxazoles, oxazolines, isoxazoles, and isoxazolines, including Diels-Alder adducts, can be prepared. [6][7][8][9][10][11][12] Recently, 1 has proven to be of interest in medical applications, acting as a reagent for preparing tachykinin receptor antagonists 13 as well as in the production of herbicides, pesticides, and insecticides. 14 In most cases, 1 is generated as a reactive dipolarophile in solution from Br-or Cl-oximes, specifically trifluoroacetohydroximoyl bromide and chloride, respectively, since it has been stated 6 to be unstable in solution "even at a temperature below -20°".…”

Section: Introductionmentioning

confidence: 99%

“…Nonetheless, they are widely used in organic chemistry for the syntheses of heterocycles and natural products, − mainly by in situ preparation and subsequent 1,3-dipolar reaction with various substrates. Trifluoroacetonitrile N -oxide, CF 3 CNO ( 1 ), is often used in [2 + 3] cycloaddition reactions where five-membered heterocycles, for example, oxazoles, oxazolines, isoxazoles, and isoxazolines, including Diels−Alder adducts, can be prepared. − Recently, 1 has proven to be of interest in medical applications, acting as a reagent for preparing tachykinin receptor antagonists as well as in the production of herbicides, pesticides, and insecticides…”

Section: Introductionmentioning

confidence: 99%

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Gas-Phase Infrared and ab Initio Study of the Unstable CF₃CNO Molecule and Its Stable Furoxan Ring Dimer

2005

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The unstable trifluoroacetonitrile N-oxide molecule, CF3CNO, has been generated in high yield in the gas phase from CF3BrC=NOH and studied for the first time by gas-phase mid-infrared spectroscopy. Cold trapping of this molecule followed by slow warming forms the stable ring dimer, bis(trifluoromethyl)furoxan, also investigated by gas-phase infrared spectroscopy. The spectroscopy provides an investigation into the vibrational character of the two molecules, the assignments supported by calculations of the harmonic vibrational frequencies using in the case of CF3CNO both ab initio (CCSD(T)) and density functional theory (B3LYP) and B3LYP for the ring dimer. The ground-state structures of both molecules were investigated at the B3LYP level of theory, with CF3CNO further investigated using coupled-cluster. The CCSD(T) method suggests a slightly bent (C(s)) structure for CF3CNO, while the B3LYP method (with basis sets ranging from 6-311G(d) to cc-pVTZ) suggests a close-to-linear or linear CCNO chain. The CCN bending potential in CF3CNO was explored at the CCSD(T)(fc)/cc-pVTZ level, with the results suggesting that CF3CNO exhibits strong quasi-symmetric top behavior with a barrier to linearity of 174 cm(-1). Since both isomerization and dimerization are feasible loss processes for this unstable molecule, the relative stability of CF3CNO with respect to the known cyanate (CF3OCN), isocyanate (CF3NCO), and fulminate (CF3ONC) isomers and the mechanism of the dimerization process to the ring furoxan and other isomers were studied with density functional theory.

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Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gas-Phase Infrared and ab Initio Study of the Unstable CF₃CNO Molecule and Its Stable Furoxan Ring Dimer

2005

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“…Nitrile oxides 1a, derived from aromatic nitriles, are the most well-known class of these 1, 3-dipoles. On the other hand, trifluoroacetonitrile oxide (1b), reported for the first time in 1971 [3,4], has rarely been used in [3+2]-cycloadditions, which are limited to reactions with alkenes and alkynes [3,5].…”

Section: Introductionmentioning

confidence: 99%

Efficient synthesis of fluoroalkylated 1,4,2-oxathiazoles via regioselective [3 + 2]-cycloaddition of fluorinated nitrile oxides with thioketones

Mlostoń

Kowalski

Obijalska

et al. 2017

Journal of Fluorine Chemistry

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Fluorinated acetonitrile oxides, generated from the corresponding hydroximoyl bromides in the presence of aryl, hetaryl, ferrocenyl, and cycloaliphatic thioketones, undergo efficient [3 + 2]-cycloadditions to give 3-fluoroalkylated 1,4,2-oxathiazoles in good to excellent yields. The reactions proceed regioselectively with no competitive formation of furoxans as dimers of the intermediate 1,3-dipoles.

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Preparation and reactions of silyl nitronates derived from 2,2,2‐trifluoronitroethane. Diastereoselective synthesis of trifluoromethyl‐substituted aminoethanols and ‐propanols

Martí¹,

Heinzer²,

Seebàch³

1995

Liebigs Ann./Recl.

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Silyl nitronates of 2,2,2-trifluoronitroethane and of l,l,l-trifluoro-2-nitropropane [SiMe3, SiMez(tBu), SiMezCMezCHMez] were prepared and their reactions studied. -The TBDMS nitronate of the nitroethane is present as the ( E ) and (Z) isomer (2.3:l at room temperature; EA = 9.3 kcal mol-l for their isomerization). Bu4NF-catalyzed silyl nitro aldol additions to aldehydes show reasonable selectivities for the formation of the syn diastereoisomers of 5-13 (ca. 4 : l ; with the non-fluorinated analogs anti isomers prevailing!). The anti epimers (5-9, 12, 13, 1?-20) in the trifluoromethyl series can be prepared by diastereoselective protonation of the corresponding 0-silyl lithium nitronates (ca. 9: 1, Scheme 3). Careful reduction of the NOz groups (Hz/Raney nickel) gives trifluoroamino alcohol derivatives (22-30, Scheme 4). -The trimethylsilyl nitronates are also used for 1,3-dipolar cycloadditions (to 1-hexene, styrene, methyl vinyl ketone, and acrylates) to give N-(sily1oxy)isoxazolidines (32-40; Scheme 5). The configuration of the major products (2,3-cis, 3,5-trans) was derived from NMR measurements, X-ray structure determinations, and thermal equilibration studies. The major course of reaction was thus derived to be an exo approach of the dipolarophiles to the (Z)-silyl nitronates (Scheme 8). -Some conversions of the W(sily1oxy)isoxazolidines (treatment with acid, base, and Raney nickel) are also described (products 42-51).Since the first report published in the early 1970s by Joffe and Tartakovskii[21, silyl nitronates of type A have become versatile reagents in synthetic organic chemistry [3]. They have found broad applications as 1,3-dipoles in 13 + 21 cycloadditi~ns[~~~] yielding isoxazolidines or, after loss of silanol, A2-isoxazolines. Silyl nitronates A are in this case synthetic equivalents of nitrile oxides, and the formed heterocycles are not only precursors to amino alcohols, but also to P-hydroxy ketones (an alternative access to aldol~[~I). On the other hand, mediated by fluoride ions, primary silyl nitronates A (R2 = H) undergo highly diastereoselective additions to aldehydes with the formation of erythro O-silylated nitro (nitro aldolsr71, cf. Henry reaction). Further examples of the reactions of silyl nitronates have been collected in some extensive review articled3].Because of the importance of fluorine-containing molecules in chemical and pharmaceutical trifluoromethyl-substituted building blocks, such as the fluoro nitro alkanes 1 and 2191 have attracted significant interest. In previous work, Baasner's group[l0I and ours ["] have described the use of 1 and 2 in aldol and Michael additions. However, the observed diastereoselectivity for the aldol addition to aldehydes was usually low. Another approach would be to use silyl nitronates 3 and 4. However, previous attempts led to mixed results with these compounds: specifically, 4a was prepared by deprotonation and trapping with tert-butyldimethylsilyl chloride on one occasion, but the experiment was not reproducible[llb1. In this paper, we repor...

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Trifluoroacetonitrile N-oxide

Cited by 4 publications

References 10 publications

Gas-Phase Infrared and ab Initio Study of the Unstable CF₃CNO Molecule and Its Stable Furoxan Ring Dimer

Gas-Phase Infrared and ab Initio Study of the Unstable CF₃CNO Molecule and Its Stable Furoxan Ring Dimer

Efficient synthesis of fluoroalkylated 1,4,2-oxathiazoles via regioselective [3 + 2]-cycloaddition of fluorinated nitrile oxides with thioketones

Preparation and reactions of silyl nitronates derived from 2,2,2‐trifluoronitroethane. Diastereoselective synthesis of trifluoromethyl‐substituted aminoethanols and ‐propanols

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Trifluoroacetonitrile N-oxide

Cited by 4 publications

References 10 publications

Gas-Phase Infrared and ab Initio Study of the Unstable CF3CNO Molecule and Its Stable Furoxan Ring Dimer

Gas-Phase Infrared and ab Initio Study of the Unstable CF3CNO Molecule and Its Stable Furoxan Ring Dimer

Efficient synthesis of fluoroalkylated 1,4,2-oxathiazoles via regioselective [3 + 2]-cycloaddition of fluorinated nitrile oxides with thioketones

Preparation and reactions of silyl nitronates derived from 2,2,2‐trifluoronitroethane. Diastereoselective synthesis of trifluoromethyl‐substituted aminoethanols and ‐propanols

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Gas-Phase Infrared and ab Initio Study of the Unstable CF₃CNO Molecule and Its Stable Furoxan Ring Dimer

Gas-Phase Infrared and ab Initio Study of the Unstable CF₃CNO Molecule and Its Stable Furoxan Ring Dimer