Sodium trifluoroacetate

Trifluoromethylation of diethyl maleate or fumarate is performed via the electrochemical oxidation of sodium trifluoroacetate [742] (equation 123)... 

DMF, dimethylformamide DMSO, dimethyl sulfoxide HFIP, hexafluoroisopropanol LiBr, lithium bromide ODCB, o-dichlorohenzene TFA-Na, sodium trifluoroacetate THF, tetrahydrofuran. 

In the case of functional polymers such as nylon, the molecular size can increase because ionic functional groups contained in the molecule repel each other. To decrease ionic repulsion, sodium trifluoroacetate should be added to HFIP. 

Smaller diameter columns are especially useful when expensive solvents are used. Figure 11.3 shows the analysis of poly (1,4-butylene terephthalate) using a Waters Alliance narrow-bore GPC system, quantitated against narrow polymethylmethacrylate standards. In this case, the solvent used is hexaflu-oro-2-isopropanol with 0.05 M sodium trifluoroacetic acid at a flow rate of... 

The syn addition of pentafluoroethyl hypofluorite (CF3CF2OF), generated in situ by the action of anhydrous, hydrogen-fluoride-free fluorine gas on sodium trifluoroacetate, to 5-acetyl-5//-dibenz[/i,/]azepine (11) has been reported to yield 12.135... 

Treatment of methyl p-chlorobenzoate with an equivalent amount of commercial potassium silanolate 97 in abs. diethyl ether affords, after 4h, pure, anhydrous potassium p-chlorobenzoate in 84% yield and methoxytrimethylsilane 13 a. Trimethylsilyl trifluoroacetate reacts hkewise with sodium trimethylsilanolate 96 in THF to give sodium trifluoroacetate, in 98% yield, and hexamethyldisiloxane 7 [119] (Scheme 4.45). 

Thermally unstable at 22°C and explosive in the gas phase at pressures above 27-62 mbar [1], there is also an explosion hazard during distillation and trapping at -78°C [2], The crude (80%) material prepared by action of 3% fluorine in nitrogen on sodium trifluoroacetate [3] has, however, been used synthetically for 3 years without mishap [4]. 

MAS has been applied to a highly viscous cubic phase of a lyotropic LC formed by 1-monooleolyl-rac-glycerol and water in order to obtain liquid-like and 13C spectra.330 Deuterium, sodium, and fluorine NMR spectroscopy have been applied to study the phase behaviour of several dilute lamellar systems formed by low concentrations of an ra-hexadecylpyridinium salt, a sodium salt (e.g., NaBr, NaCl, or sodium trifluoroacetate), 1-hexanol, and D20.331 The 2H, 19F, and 23Na splittings were used to monitor the phase equilibria. The last two studies are motivated by the search of new lyotropic LC for the alignment of biomolecules. 

Other sources of radical CF3, much less expensive than CF3I, have been discovered. These are the anodic oxidation of sodium trifluoroacetate (the decomposition being initated by a hydroperoxide or ruthenium catalyst) and trifluoromethyl bromide (CF3Br) using sodium dithionite as initiating agent. ... 

The homopropargyl rearrangement is of preparative interest for the synthesis of cyclobu-tanone and substituted cyclobutanones (Table 3). For example, the rearrangement of 4-(triflu-oromethanesulfonyloxy)but-l-yne (4) takes place almost quantitatively (76% conversion) in the presence of trifluoroacetic acid and sodium trifluoroacetate to produce cyclobutanone.6... 

Due to the cost of trifluoromethyl iodide, other cheaper sources have been investigated for trifluoromethylation. Sodium trifluoroacetate reacted with aryl iodide in the presence of copper (I) iodide in NMP at 140 -160 °C to afford the corresponding coupling product [87]. No trifluoromethylation was observed without Cul. Under similar reaction conditions, sodium pentafluoropro-pionate worked well to give the pentafluoroethylated compounds [88, 89] (Scheme 28). 

Sodium trifluoroacetate [2923-18-4] M 136.0, m 206-210°(dec). A possible contaminant is NaCl. The solid is treated with CF3CO2H and evaporated twice. Its solubility in CF3CO2H is 13.1% at 29.8°. The residue is crystd from dil EtOH and the solid dried in vacuum at 100°. [JACS 76 4285 1954]. It can be ppted from EtOH by adding dioxane, then crystd several times from hot absolute EtOH. Dried at 12O-13O°/lmm. 

The course of elemental fluorination reactions with various organic acid salts depends on the reaction conditions. The gas-solid fluorination reaction of sodium trifluoroacetate gives up to four products, whose distribution depends on the temperature of the column containing the sodium salt 1 no trifluoroacctyl hypofluoritc is formed. 

Trifluoroacetyl hypofluorite is the main product in the low-temperature fluorination of sodium trifluoroacetate in suspension in an inert solvent, and can be further transformed to pentafluoro-(fluoroxy)ethane.2 In some cases, the reaction mixture of up to four reactive products [fluoroxy, bis(fluoroxy) and acyl hypofluorites], formed in reactions with various acid salts, c.g. 5, has been directly used for the fluorination of organic molecules.1 " 5... 

Cheaper sources of tnfluoromethyl groups have been the goal of several groups The use of sodium trifluoroacetate and copper (I) iodide in dipolar aprotic solvents gave regiospecific trifluoromethylation of aromatic halides [202] (equation 136)... 

There is continued expansion in the use of metals as catalysts in substitution reactions. Copper iodide in the presence of /V./V -dimcthylcthylcncdiamine has been shown to be effective in the intramolecular substitution of aryl bromides carrying an o-l,3-dicarbonyl substituent reaction may involve either an oxygen centre or a carbon centre of the dicarbonyl moiety.26 The reaction of aryl halides with sodium trifluoroacetate in the presence of copper iodide may lead to the formation of the tri-fluoromethylated derivatives, possibly via CF3CuI as an intermediate.27 There have been theoretical calculations, PM3 and ab initio, on complexes formed from copper... 

A similar rearrangement has been performed on furanosic derivatives, by a Sn2 displacement of a triflate protecting group at C-5, using sodium trifluoroacetate.173 Thus, 1,2-0-isopropylidene-/l-L-idofuranurono-6,3-lactone (59) has been prepared from 1,2-O-isopropylidene-a-D-glucofuranu-rono-6,3-lactone (40). 

Bis(trifluoromethyl) trioxide, CF3OOOCF3, was probably first prepared in low yield (<5%) from the fluorination of sodium trifluoroacetate.1 A substance of this composition was also... 

Coupling of aryl iodides has also been effected with perfluoroalkylcoppers and perfluo-rovinylcopper reagents51,13. The former reaction may also be accomplished by employing the perfluoroalkylsilane, the aryl iodide and stoichiometric amounts of KF2. Trifluoromethylation may also be accomplished, in more modest yields, by decarboxylation of sodium trifluoroacetate in.the presence of Cul and an aryl iodide71. Stannylation has been accomplished of aryl halides by the use of h.o. stannylcyanocuprates (equation 50)72. 

The nucleophilic nature of this reagent is confirmed by the p-value + 0.46 obtained from the crude Hammett plot of the reaction of p-substituted iodoaromatics with the trifluoromethylating system sodium trifluoroacet-ate / copper iodide [88JCS(P1)921]. Consequently, electron-withdrawing substituents enhance reactivity, whereas electron-donating substituents (—OH, —NH2) inhibit the reaction. 

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