Trifluorobenzene, reaction

Trifluorobenzene. This compound is formed ia low yield (13—24%) from l,2,3-trichloroben2ene or 2,3-difluorochloroben2ene and KF/CsF ia dimethyl sulfone (204). Likewise, low yields are reali2ed when the Bal2-Schiemann reaction is appHed to 2,3-difluoroaniline or... 

Trifluorobenzene. This isomer, j -trifluoroben2ene, has been prepared ia 63% yield by the Bal2-Schiemann reaction with... 

Reaction of 2-aminobenzyl alcohol with butenesulfonyl chloride gave 700 which upon treatment with BuLi followed by COCI2 gave the benzoxazine 701. Thermolysis of 701 in 1,2,4-trifluorobenzene gave the thiazoloquinoline 702 (96JCS(P1)1809) via an intramolecular Diels-Alder reaction (Scheme 121). 

The examples given demonstrate that l,3,5-trichloro-2.4,6-trifluorobenzene can be dispropor-tionated either with or without an additive. Aluminum trifluoride and chromium(III) fluoride act as catalysts and enhance the reaction boron trifluoridc, however, seems to act as an inhibitor. 

Place 2400 milliliters of 30% fuming sulfuric acid into a 6-liter 3-neck flask equipped with a stirrer and thermometer, and then cool the acid to 0 Celsius by means of an ice bath. Then, while maintaining the acid at 0 Celsius and stirring, slowly add 560 grams of potassium nitrate in small portions over a 2-hour period. After the addition of the potassium nitrate, remove the ice bath, and then place the reaction mixture into a hot water bath at 50 Celsius. Then slowly add 112 grams of 1,3,5-trifluorobenzene over a period of 2 hours while maintaining the temperature of the reaction mixture at 50 Celsius and stirring. 

The ipso protonation deserves a special scrutiny is discussed earlier. Here we show that the additivity rule is operative for the ipso protonation too, if proper reference level is found. Let us consider multiply substituted fluorobenzenes. They are schematically depicted in Fig.7. It is obvious that the proton affinity of benzene cannot serve as a gauge value for the ipso protonation. Instead, we shall employ once again homodesmic reactions and proceed as follows. Protonation at position 1 of 1,2,3-trifluorobenzene will provide an illuminating example in this respect. The corresponding homodesmic reactions read ... 

An analogous version of the Biginelli reaction was also developed 2.l3 following the same strategy. In addition, fluorinated stannane reagents have been used in Stille-type couplings. The usually tedious separation of stannanes from the products could be achieved by simple extraction with trifluorobenzene. ... 

The corresponding 3>chIorotetrafluoro- and 2,6-diiluoro-phenyl compounds undergo similar reactions, and when treated with potassium fluoride in the presence of iodine yield the corresponding iodo-compounds presumably the reactions involve formation of halogenophenyl carbanions. This is supported by the observation that 3-chlorotetrafluoro- and 3,5-dichloro-trifluorophenyl(trimethyl)silanes yield SiMej-terminated polyphenylenes when heated alone with potassium fluoride in DMF (Scheme 47), and the dichlorotrifluoro-compound yields l,3-dichloro-2,4,6-trifluorobenzene in the... 

The ISQ sequence may be illustrated through the example of trisUylation of 1,3,5-trifluorobenzene 24 (Scheme 26.6). In contrast to what was stated in an early report pubhshed 40 years ago and regularly quoted in the literature since then [127], the reaction between 1,3,5-trifluorobenzene 24 and an excess of f-BuLi and subsequent treatment with an excess of TMSCl at -115°C affording l,3,5-trifluoro-2,4,6-tris(trimethylsilyl)benzene 26 does not occur via the trditfaiated species 25. 

Cerium(IV) fluoride is suitable for the fluorination of benzene (Hudson et al., 1969). The reaction was carried out by passing benzene vapor over heated cerium(IV) fluoride at temperatures between 250 °C and 480 °C. Below 400 " C little fluorination takes place, but above 410 °C the reaction rate increases rapidly. The reaction leads to a mixture of fluorinated compounds. For instance, the following products were isolated from the reaction mixture after fluorination at 480°C fluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,4-trifluorobenzene, 1,2,4,5-tetrafluorobenzene, 1,2,3,4-tetrafluorobenzene and different fluorinated cyclohexenes and cyclohexadienes. Benzotrifluoride (trifluoromethylbenzene) was also fluorinated by the same procedure (Hudson and Pedler, 1970). Asovich et al. (1994) describe the use of cerium(IV) fluoride for the fluorination of ethylene. The extent of fluorination depends on the temperature the higher the temperature, the more fluorine atoms are bound to the ethylene molecule. The composition of the mixture formed by reaction between ethylene... 

Perumal and Sridhar [190] also reported a modified method for synthesis of 1,4-dihydropyridines 99 by reaction of aldehydes with enaminoesters and )S-ketoester in the presence of [BM1M][C1] in a molar ratio of 1 5 (reactant/IL) and 3,4,5-trifluorobenzene boronic acid (5 mol %) as catalyst at RT (Scheme 52). They used enaminoesters 98 as a source of ammonia and described the methodology advantageous in terms of yield and reaction time over the conventional method such as refluxing in ethanol required 8h to afford product in 48% yield. The IL was also recovered and reused twice with no appreciable decrease in yield [190]. 

Both and F n.m.r. data have been employed in the assignment of 2,5-difiuorophenyl methyl sulphide as the structure of the product of reaction between MeS Na+ and 1,2,5-trifluorobenzene. ... 

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