Fluoromethyl formate

Kutsuna, S., Chen, L., Abe, T., Mizukado, J., Uchimaru, T., Tokuhashi, K., and Sekiya, A. Henry s law constants of 2,2,2-tri-fluoromethyl formate, ethyl trifluoroacetate, and non-fluorinated analogous esters, Atmos. Environ., 39(32) 5884-5892,2005. 

Fluoromethoxycarbene ( CFOCH3), 115 Fluoromethyl formate, 263 structure, 263 Fock equations, 23 Fock operator, 35 FOOF, 258... 

Phenols with an appropriate leaving group in the benzylic position such as fluoride may form QMs by spontaneous hydrolysis, possibly catalyzed by a basic amino acid residue as shown in Scheme 10.2c. Evidence for this process was obtained with 4-(fluoromethyl)phenyl phosphate involving initial enzymatic hydrolysis of the phosphate followed by nonenzymatic formation of a QM.11 Similarly, several lines of evidence demonstrate nonenzymatic QM formation from 4-trifluoromethylphenol under physiologic conditions.12... 

In spite of all efforts, only very few (fluoromethyl)silicon compounds (CH3.nFn)Si= have been described up to now. In contrast to their CH3Sis analogues they are both difficult to obtain, and are very unstable because of ease of carbene elimination, with concomitant formation of SiF bonds. 

A type iii-d reaction leads to the formation of (69). Trifluoromethyl radicals generated electrochemically from triflu-oroacetate can attack electron-deficient olefins leading to trifluoromethylated carbon radicals whose chemical and electrochemical follow-up reactions can be controlled by current density, reaction temperature, and substituents of the olefins. With fumaronitrile (86) at 50 °C the monotri-fluoromethylated compound (87) was obtained in 65% yield (Scheme 31) [110]. 

Hi. Lysine. Gamma radiolysis of aerated aqueous solution of lysine (94) has been shown, as inferred from iodometric measurements, to give rise to hydroperoxides in a similar yield to that observed for valine and leucine. However, attempts to isolate by HPLC the peroxidic derivatives using the post-column derivatization chemiluminescence detection approach were unsuccessful. This was assumed to be due to the instability of the lysine hydroperoxides under the conditions of HPLC analysis. Indirect evidence for the OH-mediated formation of hydroperoxides was provided by the isolation of four hydroxylated derivatives of lysine as 9-fluoromethyl chloroformate (FMOC) derivatives . Interestingly, NaBILj reduction of the irradiated lysine solutions before FMOC derivatization is accompanied by a notable increase in the yields of hydroxylysine isomers. Among the latter oxidized compounds, 3-hydroxy lysine was characterized by extensive H NMR and ESI-MS measurements whereas one diastereomer of 4-hydroxylysine and the two isomeric forms of 5-hydroxylysine were identified by comparison of their HPLC features as FMOC derivatives with those of authentic samples prepared by chemical synthesis. A reasonable mechanism for the formation of the four different hydroxylysines and, therefore, of related hydroperoxides 98-100, involves initial OH-mediated hydrogen abstraction followed by O2 addition to the carbon-centered radicals 95-97 thus formed and subsequent reduction of the resulting peroxyl radicals (equation 55). 

Selective formation of 2,2,3,3,3-pentafluoropropan-l-ol (1) is achieved using 80% aqueous hydrofluoric acid or hydrogen fluoride/sulfuric acid mixtures.210 Furthermore, hexafluoro-propene reacts selectively under such modified conditions to give 2,3.3,3-tctrafluoro-2-(tri-fluoromethyl)propan-1-ol (2).210 Symmetrical fluoro-containing ethers 3 are obtained by reaction of 1,1-difluoro- or 1,1-dichloroethene, respectively, with 15% paraformaldehyde in hydrogen fluoride (1-chloroethene reacts analogously).204,21 1,212... 

Carboxylates may also be obtained by a modified fluoromethylation reaction. Thus, hydrogen fluoride/formaldehyde. 1,1-dihaloethene and acetic acid react to give FX2CCH2CH2OAc. However, the formation of the above described fluoro-containing symmetrical ethers is an important competitive reaction.205 Common alkenes. such as propene, are less suitable for carrying out fluorohydroxymethylations because of their high tendency to polymerize. 

Furan-2,3.4-tricarboxylic acid,155 2-(trifluoromethyl)furandicarboxylic acids.152 and tris(tri-fluoromethyl)-2-furoic acid.156 even in excess hydrogen fluoride and under forcing reaction conditions, give exclusively the corresponding poly(trifluoromethyl)furans. e.g. formation of 14 no addition of fluorine to the ring carbons occurs. 

This method has been extended to heterocycles bearing a hydroxymethyl-substituted nitrogen. Thus, ethyl l-(hydroxymethyl)pyrazole-4-carboxylate (10) is converted into ethyl 1-(fluoromethyl)pyrazole-4-carboxylate (11) in 76% yield with cesium fluoride/methanesulfonyl fluoride/18-crown-6 system.167 Potassium fluoride did not react at all and tetrabutylammonium fluoride leads to decomposition and formation of coupling products. 

A neutral diazo compound can be considered as both a nucleophile and an electrophile. Thus, it can be substituted by the combination of an electrophilic moiety and a nucleophilic moiety (X+ Nu ") (Scheme 8). In practice, the diazomethyl group is transformed to the fluoromethyl group by treatment with hydrogen fluoride/pyridine mixture (70 30 w/w) (X = H Nu = F), or to the halofluoromethyl group by addition of A-halosuccinimide in the same medium (X = Cl, Br, I Nu = F), e.g. formation of l.16 The reaction can be performed on secondary diazo alkanes, diazo ketones or diazo esters.16 90 316... 

Further examples of dehydrofluorinations of heterocyclic compounds can be found in refs 113 (formation of fluorinated dihydrofuran derivatives), 114 [formation of 3-fluoro-2,2-bis(tri-fluoromethyl)-2//-oxete], and 115 (formation of fluorinated 2,3-dihydro-l, 4-dioxin derivatives). 

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... 

Bell and co-workers 24, 25) have investigated the generation of tri-fluoromethyl radicals from photolysis of HFA in the presence of silanes. Abstraction of the proton is observed in the case of trichlorosilane (24), while methyl(fluoro)silanes lead to the formation of CFjH, CjF, and CF CH 2(25). 

Other examples of favored formation of cyclobutanes include photocycloadditions of tri-fluoromethyl-substituted coumarins with dienes,and of 5-(trifluoromethyl)-l,3-dioxin-4-ones, e.g. 3, with alkenes, " - - " as well as intramolecular photocycloadditions, such as those of bicyclo[2.2.2]octadiene and tricyclononadiene derivatives. 

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