Perfluorinated tetrahydrofurans

The most common method for the preparation of perfluorinated tetrahydrofurans is fluorination of tetrahydrofurans. Elemental fluorine or high-valency metal fluorides (AgF2, Mnp3, Hgp2, and Cop3) are usually used as fluorinating agents. ... 

Glass from an acychc monomer by means of a cyclopolymerization. The resulting polymer contains a perfluorinated tetrahydrofuran ring and has a Tg of 108°. The polymerization of... 

Similarly, the zirconocene system transforms perfluorinated Decalin to perfluoronaphthalene and its 2//-derivative (15)159 at room temperature. When the starting mixture is reacted for 14 h, the dominant organic product is 2//,6//-hexafluoronaphthalene (16), formed by subsequent reduction of 15. Deuterium incorporation in 15 and 16 from tetrahydrofuran-r/8 demonstrates that the solvent is a hydrogen source.159... 

Hazardous perfluorination processes with high yields were carried out safely in microreactors, such as the perfluorination of tetrahydrofuran and cyclohexane derivatives [309]. 

This route is especially valuable for the transformation of electron-rich heteroaromatic compounds into their fluorinated analogues, which are not suitable for the nucleophilic exchange route. The method has been extended by addition of fluorinated olefins. The fluoroolefins add in a radical process to the 2-position of tetrahydrofuran, followed by perfluori-nation to give the perfluorinated 2-alkyl-substituted tetrahydrofurans in excellent yields [84JFC(25)523 85JFC(29)323] (Scheme 3). 

High molecular weight perfluorinated tertiary alcohols can be prepared by the reaction of (perfluoroalkyl)- and (perfluorooxaalkyl)trimethylsilanes with fluoro ketones (vide supra). The reaction has been extended to carbonyl compounds other than ketones acid fluorides gave ketones, but no reaction was observed with esters. a-Oxo esters react with trimethyl(tri-fluoromcthyl)silane with fluoride initiation in tetrahydrofuran /(./(. -trifluoro lactic acid derivatives are produced in good yields in one step. 

The ability of perfluorinated ethers to react with anhydrous AICI3 at elevated temperatures was discovered by Tiers. While the reaction of alicychc perfluorinated ethers results in the cleavage with the formation of acyl chloride and chloro-fluoroalkanes, perfluorinated a-aUcyl tetrahydrofuranes undergo replacement of all three a-fluorines with the formation of cyclic a,a,a-trichloro derivatives. Later, this reaction was extensively studied by Abe (Fig. 9... 

Cyclic ethers such as tetrahydrofurans, 1,4-dioxane, and oxalanes subjected to ECF in anhydrous HF are converted into perfluorinated derivatives (Tables 19 and 20) (85JES2424, 67ZOB1229, 74ZPK590) (Scheme 53). 

Perfluorination of tetrahydrofuran and cyclohexane derivatives can be achieved to give the perfluorinated product in high yield (Scheme 8.6). These hazardous perfluorination processes can be carried out safely in single-channel microreactors with high yields. 

Luque N, Ballesteros-Gomez A, van Leeuwen S, Rubio S. Analysis of perfluorinated compounds in biota by microextraction with tetrahydrofuran and liquid chroma-tography/ion isolation-based ion-trap mass spectrometry. J Chromatogr A 2010 1217(24) 3774-82. 

The five kinds of perfluorinated diamines listed in Figure 3 were added to tetrahydrofuran (THF) with equimolar amounts of phthalic anhydride to a concentration of 10 wt% and stirred at room temperature for 7 days. The monoa< derivatives were slowly precipitated and washed n hexane. From the C, H, and F NMR, the powder samples thus obtained were mixtures of MAD, diamine, phthalic anhy de, and dKamic add). However, and NMR signals of amino groups of MADs were easily assigned. For 8FBZ diamine, no signals of MAD and di(amic add) was observed. 

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