The first Cu(I)-mediated nucleophilic trifluoromethylation reactions using (trifluoromethyl)trimethylsilane in ionic liquids

The new ionic liquids (5a - 8a) were used as reaction media for nucleophilic trifluoromethylation reactions of trifluoromethyl( trimethyl) silane with (1) aryl, allyl, benzyl, and alkyl halides in Cu(I)-mediated C - C bond formation reactions, and ( 2) carbonyl functionalities catalyzed with Ph3P or CsF. In addition, conversion of benzyl bromide as a model compound to benzyl fluoride was examined in 6a using CsF as the fluorinating reagent. The morpholinium-based ionic liquid ( 6a) stood out as an efficient solvent system comparable to organic solvents and superior to the other new ionic liquids prepared in this work as well as to [bmim](+)[PF6](-). Neat reactions of N-methyloxazolidine ( 1), N-methylmorpholine ( 2), N-methylimidazole ( 3) or N-methyltriazole ( 4) with 2-(2-ethoxyethoxy) ethyl bromide (BrCH2CH2OCH2CH2OCH2CH3, 9) or 2- bromoethyl methyl ether (BrCH2CH2OCH3, 10) at 75 or 105 degreesC gave the N-(2- ethoxyethoxy)ethyl- or N-methoxyethyl-substituted oxazolidinium, morpholinium, imidazolium and triazolium quaternary bromides (1a - 4a, 1b - 4b) which were metathesized with LiN(SO2CF3)(2) to form the respective room-temperature liquid bis(trifluoromethanesulfonyl) amides 5a - 8a and 5b - 8b in high yields with transition or melting points <- 78 degrees C as determined by DSC. All of the ionic liquids are thermally stable to > 310 degreesC as determined by thermogravimetric analyses (TGA). Densities range between 1.29 and 1.53 g cm(-3) at 25 degreesC.