5- -3-phenyl- -trifluoroacetate

For the three reactions represented in Fig. 12 the maximum rate of hydrolysis in acid represents only a mpdest acceleration, compared with the rate in initially neutral solution. Bunton and Hadwick89,90 explained the maximum for methyl and phenyl trifluoroacetate in terms of negative salt effects on both acid-catalyzed and neutral reactions. Consistent with this interpretation, it was demonstrated directly that the rate of neutral hydrolysis is decreased by added salts. The effect of added salt should be to decrease the activity of water, and perhaps also to salt in the ester. 

Electron-poor arenes can be converted into phenols by anodic oxidation [40]. A mixture of ortho-, meta- and para-substituted phenols is obtained in 18-89 % yields (Eq. (8) TFA is trifluoroacetic acid). Aryl trifluoroacetate is formed first and then hydrolyzed to phenol in a separate step. The oxidation potential of phenyl trifluoroacetate is higher than that of phenol, which explains the absence of overoxidation. 

Lead tetrakis(trifluoroacetate), Pb(OCOCF3)4, which is prepared from red lead oxide (Pb304), trifluoroacetic acid, and trifluoroacetic anhydride [435], has very limited applications. It converts alkylbenzenes into benzylic trifluoroacetates [435] and benzene and its derivatives into phenyl trifluoroacetates [435, 449]. 

The important drop in the yields from primary to secondary alcohols was attributed in part to a competing trifluoroacetylation induced by the presence of phenyl trifluoroacetate, a decomposition product of the reagent (6). Reaction of 3p-cholestanol (77) with (6) led the 0-phenyl ether (78) in 29% yield, together with 3P-cholestanyl trifluoroacetate (79) in 65% yield. 

Use in peptide synthesis.1 The reagent reacts with N-pro-tected amino acids by ester interchange to give active esters 2 -nococf3 of use in synthesis. Only very slight racemization is observed.2 CHzCW0 Use of p-nitrophenyltrifluoroacetate or of 2,4,5-trichloro-phenyl trifluoroacetate leads to complete racemization. (i)... 

The rate of reaction of carboxylic esters with amines can often be increased by using as acylating agents esters that exchange their alcohol residues with particular ease. With this in mind Schwyzer781 recommends the use of cyano-methyl esters, RCOOCH2CN. The cyanomethyl esters of N-protected amino acids react readily even at room temperature with amino esters and are thus particularly suitable for peptide synthesis. Also, phenyl trifluoroacetate has been recommended for trifluoroacetylation of amino acids and peptides.782 The possibilities offered by such activated esters for peptide synthesis are reviewed in the monograph by Schroder and Liibke.783... 

In some cases POMs can oxygenate hydrocarbons. For example, the oxidation of alkanes and benzene by poly vanadate in CF3COOH to produce alkyl (phenyl) trifluoroacetates and ketones is stimulated by light [85]. In fact, the alkane and benzene reactions with the vanadate virtually do not proceed in the absence of light. On the other hand, ethylbenzene and toluene are rapidly oxidized in the dark reaction, even at 10 °C. 

Phenyl trifluoroacetate (149) undergoes oxidative addition to generate the acyl-palladium 150 [64], Based on this reaction, trifluoromethyl ketones such as 151 can be prepared by Suzuki coupling with arylboronic acids. Similarly, anisyl heptafluoropropyl ketone (154) was prepared by the Suzuki coupling of phenyl heptafluorobutyrate (152) with anisylboronic acid 153 [65]. 

Phenyl trifluoroacetate treated with a ca. 10% excess of diazomethane at room temp, in the dark for 2 h 2-(trifluoromethyl)-2-phenoxyoxirane. Y 68%. The method is... 

A soln. of trifluoroacetic acid, phenyl chloroformate, and triethylamine in tetra-hydrofuran gently refluxed for 1 hr., the resulting triethylamine hydrochloride removed by filtration, and the filtrate distilled phenyl trifluoroacetate. Y 75-80%. M. Green, Ghem. Ind. 1961, 435. 

Cobalt(iii) trifluoroacetate is a strong oxidant formed by the equilibration of di- -hydroxo-diacetatocobalt(m) in trifluoroacetic acid (TFA). In this medium facile oxidation of hydrocarbons is observed, in that benzene yields phenyl trifluoroacetate and ethylene is converted into ethyleneglycol ditrifluoroacetate ... 

Uncatalysed resole phenolic resins have excellent storage stability, but add catalysed ones have only a limited life at room temperature. Latent add catalysts have been developed to overcome this problem. They are used in readion injection moulding (RIM) and in resin transfer moulding (RTM) processes. Examples are phenyl hydrogen maleate, phenyl trifluoroacetate and butadiene sulfone. At elevated temperatures these catalysts generate the corresponding acids, which catalyse the resole reactions. A cycle time of one to two minutes at 150°C is achievable. The choice of a suitable latent catalyst can also reduce the peak exotherm temperature. 

From the results of a kinetic study of a series of X-phenyl trifluoroacetates (11 X = 4-Me, H, 4-F, 4-Cl, 3-Cl), it was concluded that, as is the case for aryl acetates and formates, aryl trifluoroacetates are hydrolysed by a concerted mechanism." Another... 

Obtained in small amount by Fries rearrangement of phenyl trifluoroacetate with aluminium chloride without solvent at 90 [4691]. 

JL. C0CF3 - PteparadonbyFriesreanangementof4-hexyl-3-hydroxy-p" ij phenyl trifluoroacetate with aluminium chloride at... 

Preparation by Fries rearrangement of 3-hydroxy-2-(4-methylcyclohexyl)phenyl trifluoroacetate with aluminium chloride in nitrobenzene or withont solvent at 120° [4689]. 

Pyridinecarboxaldehyde, P-00319 Phenyl trifluoroacetate, in T-00239 Indophenol, 1-00034 >CafFeic acid, in D-00716... 

However, this method is appHed only when esterification cannot be effected by the usual acid—alcohol reaction because of the higher cost of the anhydrides. The production of cellulose acetate (see Fibers, cellulose esters), phenyl acetate (used in acetaminophen production), and aspirin (acetylsahcyhc acid) (see Salicylic acid) are examples of the large-scale use of acetic anhydride. The speed of acylation is greatiy increased by the use of catalysts (68) such as sulfuric acid, perchloric acid, trifluoroacetic acid, phosphoms pentoxide, 2inc chloride, ferric chloride, sodium acetate, and tertiary amines, eg, 4-dimethylaminopyridine. 

This thiourea, prepared from an amino acid and phenyl isothiocyanate, is cleaved by anhydrous trifluoroacetic acid (an N-COCF3 group is stable), and by oxidation (/72-CIC6H4CO3H, 0°, 1.5 h, 73% yield H2O2/ACOH, 80°, 80 min, 44% yield). ... 

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