557-99-3Relevant articles and documents
Satchell
, p. 1752,1754 (1960)
Coordination modes and reaction of acetic anhydride with tantalum pentafluoride
Il'In,Kovalev
, p. 111 - 114 (2014)
The composition and structure of compounds formed upon the reaction of equimolar amounts of TaF5 and MeC(O)O(O)CMe in CH2Cl 2 and upon dissolution of the fluoride in an anhydride excess have been studied by 19F NMR (293-183 K). It has been found that, in both cases, the anhydride is fluorinated to form MeC(O)F (a quartet at 47.7 ppm, J FH = 18 Hz) and the MeC(O)O- anion. In the spectra of the reaction mixture in CH2Cl2, the signals of pentafluoro complexes are assigned to the TaF5[OC(Me)OC(O)Me] adduct and the TaF5[OC(O)Me]- anion; on the basis of the chemical shifts of the singlets, they are assigned to the TaF4[OC(Me)OC(O)Me] + and TaF2[OCOC(O)Me] 2 3+ cations in which the anhydride acts as a chelating ligand. Upon the direct reaction of the reagents in an anhydride excess, the spectra at low temperatures show, in addition to the signal of the tetrafluoride cation, the signals of the hexafluorotantalate ion TaF 6 - and four trifluoroacetate complexes. Close relative concentrations of the latter enable the suggestion that they form chain or cyclic structures. It is believed that, in these structures, the acetate group has monodentate and bridging coordination modes, while chelating coordination mode seems to be less probable.
-
Swain,Scott
, p. 246 (1953)
-
Preparation of 2,3,3,3-tetrafluoropropene from trifluoroacetylacetone and sulphur tetrafluoride
Banks, R. Eric,Barlow, Michael G.,Nickkho-Amiry, Mahmood
, p. 171 - 174 (1997)
Practical details are presented for the laboratory preparation of 2,3,3,3-tetrafluoropropene in good yield from trifluoroacetylacetone and sulphur tetrafluoride in the presence of hydrogen fluoride. The gas-phase IR spectrum of the tetrafluoropropene (b.p., -28 °C) is reproduced and a detailed analysis of the olefin's nuclear magnetic resonance (NMR) spectra (1H, 13C, 19F) is provided.
Deoxyfluorination of Carboxylic Acids with KF and Highly Electron-Deficient Fluoroarenes
Mao, Siyu,Kramer, Jordan H.,Sun, Haoran
, p. 6066 - 6074 (2021/05/29)
A deoxyfluorination reaction of carboxylic acids using potassium fluoride (KF) and highly electron-deficient fluoroarenes is reported here, giving acyl fluorides in moderate to excellent yield (57-92% based on NMR integration and 34-95% for isolated examples).
Concise Modular Synthesis and NMR Structural Determination of Gallium Mycobactin T
Chan, Kiat Hwa,Groves, John T.
, p. 15453 - 15468 (2021/11/16)
A modular synthesis of mycobactin T and its N-acetyl analogue is reported in a route that facilitates permutation of the lipid tails. A key feature is the generation of N(α)-Cbz-N(?)-benzyloxy-N(?)-Boc-lysine (A4) with methyl(trifluoromethyl)dioxirane in 59% yield. Selective hydroxamate N-acylation was achieved with acyl fluorides, enabling installation of lipids tails in the final step. O-Benzyl-dehydrocobactin T (B4) was prepared by modifying a known five-step sequence with an overall yield of 49%. 2-Hydroxyphenyl-4-carboxyloxazoline (C3) was prepared from 2-hydroxybenzoic acid and l-serine methyl ester in three steps with an overall yield of 55%. Ester coupling of A4 and B4 with EDCI afforded MbI-1 in 73% yield. Catalytic hydrogenation with Pd/BaSO4 and 50 psi of H2 simultaneously effected alkene reduction and debenzylation to afford MbI-2 in 96% yield. Fragment C3 was converted into acyl fluoride C4, which coupled with MbI-2 to afford MbI-3 in 51% yield. Finally, Boc-removal with HCl/EtOAc and treatment of the resultant hydroxylamine with stearyl fluoride furnished mycobactin T in 65% yield. Overall, the yield is 4% over 14 steps. The gallium mycobactin T-N-acetyl derivative (GaMbT-NAc) structure was determined by 1H NMR. The structure shows an octahedral Ga and two internal hydrogen bonds between peptidic N-Hs and two of the oxygen atoms coordinating Ga.
Organocatalyzed Fluoride Metathesis
Mulryan, Daniel,White, Andrew J. P.,Crimmin, Mark R.
supporting information, p. 9351 - 9355 (2020/11/30)
A new organocatalyzed fluoride metathesis reaction between fluoroarenes and carbonyl derivatives is reported. The reaction exchanges fluoride (F-) and alternate nucleophiles (OAc-, OCO2R-, SR-, Cl-, CN-, NCS-). The approach provides a conceptually novel route to manipulate the fluorine content of organic molecules. When the fluorination and defluorination steps are combined into a single catalytic cycle, a byproduct free and 100% atom-efficient reaction can be achieved.
