Trifluoroethyl ether

Chemically, 2,2,2-trifluoroethanol behaves as a typical alcohol. It can be converted to trifluoroacetaldehyde [75-90-1] or trifluoroacetic acid [76-05-1] by various oxidi2iag agents such as aqueous chlorine solutions (51) or oxygen ia the preseace of a vanadium pentoxide catalyst (52). Under basic conditions, it adds to tetrafluoroethylene and acetylene to give, respectively, 1,1,2,2-tetrafluoroethyl 2/2/2 -trifluoroethyl ether [406-78-0] (53) and... 

Common Name Hexafluorodiethyl ether bis(trifluoroethyl) ether... 

The crude product was washed successively with concentrated HCI, 62% HjSO, concentrated HjSO and 5% NaOH solution. It was dehydrated over a drying agent and then refractionated in a still. 20 parts of bis(2,2,2-trifluoroethyl) ether were recovered (BP 62.5° to 63.5°C). 

Regarding proton spectra, as was the case with 2,2,2-trifluoroethyl chloride (Scheme 5.7), the chemical shifts of the CH2 protons of 2,2,2-tri-fluoroethanol and of 2,2,2-trifluoroethyl ethers are more affected by the OH or ether substituents than they are by the CF3 group. 

A large number of fluorinations of partially fluorinated ethers have been successfully carried out. A few examples are fluorination of methyl 2,2,2-trifluoroethyl ether (12),85 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (13),85 2-(l,l,2,3,3,3-hexafluoropropyl)tetrahydro-furan (14),86 difluoromethyl 2,2,2-trifluoroethyl ether (15),10 and bis(2,2,2-trifluoroethyl) ether (16).10 Manganese(III) fluoride is more reactive than cobalt(III) fluoride in the last two fluorinations. 

Alkylation or acylation of ketones, sulfides, and amines. This reagent generally reacts with alcohols or carboxylic acids to form 2,2,2-trifluoroethyl ethers or esters in satisfactory yields, except in the case of alcohols prone to dehydration. The reaction of these ethers provides a simple synthesis of unsymmctrical sulfides (equation I). A similar reaction can be used for preparation of secondary amines or amides (equation II). Enolatc anions (generated from silyl cnol ethers with KF) can be alkylated or acylated with a or b (equation III). Use of Grignard reagents in this type of coupling results in mediocre yields. 

It has been demonstrated that in alkyl 2-chloro-l,l,2-trifluoroethyl ethers, e.g. 5. both x-and /J-C-F bonds can be reduced, though in low yield, by lithium aluminum hydride in diethyl... 

Perfluorobenzene and 2,2,2-trifluoroethanol can be refluxed in pyridine in the presence of sodium hydroxide to give pentafluorophenyl 2,2,2-trifluoroethyl ether (ll).88... 

A situation of this type was encountered in the investigation of the solvolysis of benzyl azoxytosylate, 14 in Fig. 9.6, in aqueous trifluoroethanol [23]. In the absence of added nucleophilic reagents the products were benzyl alcohol and benzyl trifluoroethyl ether. Added excess sodium thiocyanate had minimal effect upon the rates, but the reaction then yielded substantial amounts of benzyl thiocyanate. The plot of the inverse mole fraction of benzyl thiocyanate against 1/ [NaSCN], shown in Fig. 9.6, is linear with a non-zero intercept, consistent with the intermediacy of a species trappable by thiocyanate, and a competing pathway for the formation of ethereal and alcoholic products other than via this species. 

Some explicit examples of 1,1,2-trifluoroethyl ethers and sulfides are provided in Scheme 6.1. 

Wu, K. Chen, Q.-Y. Synthesis of trifluoroethyl ethers from 2,2,2-trifluoroethyl chloride in high temperature aqueous medium. /. Fluorine Chem. 2002, 333, 79-83. 

Common Name Hexafluorodiethyl ether Bis(trifluoroethyl) ether Structural Formula ... 

A clever synthesis of benzofurans, benzothiophenes and indoles starts with the trifluoroethyl ethers 425 and uses a 5-endo-dig cyclisation. Four equivalents of rc-BuLi perform two eliminations, one substitution, and one lithiation to generate aryllithium 426, which undergoes 5-endo-dig cyclisation. 3-Butylbenzofuran is generated in 40% yield.186... 

Trifluoroacetyl hypochlorite, 419 Trifluoroacetyl hypoiodite, 419 2,2,2-Trifluoroethyl ethers, 43 Trifluoromethanesulfonic anhydride, 419-420... 

Leenheer et al. (1983) have also prepared the trifluoroethyl ethers of humic materials by reaction of a sample suspended in methylene chloride with trifluorodiazoethane. Proton, C, and NMR of this derivative provide information on the concentration of aliphatic hydroxyl groups. 

Flurothyl [555-56-8] (bis-(2,2,2-trifluoroethyl)ether) (9), an analeptic having strong convulsant properties, has been used for chemical shock therapy (13). The compound is unique in that it is a volatile fluorinated ether and its structure resembles those of many halogenated general anesthetics. Chemical shock therapy is rarely used. 

---