Triflimide salt

Davis recently reported triflimide salts derived from classical Girard s reagents which are hydrazine derived onium salts [29],... 

Bhowmik PK, Han HS, Cebe JJ et al (2003) Ambient temperature thermotropic liquid crystalline viologen bis(triflimide) salts. Liq Cryst 30 1433-1440... 

Bhowmik PK, Han HS, Nedeltchev IK et al (2004) Room-temperature thermotropic ionic liquid crystals viologenbis(triflimide) salts. Mol Cryst Liq Cryst 419 27-46... 

Both pyridinium and imidazolium ionic liquids have been used as solvents for palladium-catalysed reactions, such as the Suzuki coupling, but only the use of l-(3-cyanopropyl)pyridinium triflimide salt (mp -64.5 °C) allows very efficient retention and recycling of the palladium catalyst. ... 

Metal triflimide salts were foimd to be excellent catalysts for Friedel-Crafts acylation reactions of aromatic compoimds [47,71]. Although these salts wiU catalyze the reaction by themselves, their reactivity is increased significantly when dissolved in triflimide ionic liquids, and the ionic liquid/catalyst can be recycled [71]. Surprisingly, the metal triflimides with the greatest activity were those of cobalt(ii), nickel(ii), manganese(ii), iron(iii) and indium(iii) (Scheme 5.2-27). 

Abstract Room temperature ionic liquids (ILs) have attracted considerable attention as novel reaction media over the last decade. By virtue of their unique properties, ILs have been proposed as alternative solvents. Structurally, most of the ILs that have been investigated to date are based on imidazolium, pyridinium and ammonium cations, associated with polyatomic anions such as chloroaluminates, tetrafluoroborate, hexafluorophoshate and bis-triflimide. Although these salts have positive properties, imidazole, pyridine and halogenoalkanes come from petroleum feedstocks that are neither green nor sustainable. Renewable resources may represent a valid alternative to synthesized new ILs an alternative able to take into accounts both the ecological and economic requirements. 

Moreover, the popularity of tetrafluoroborate and hexafluorophosphate imidazoliiun salts and the improved properties evidenced more recently by ILs having bis(triflimide) as anion have probably discouraged the research of new anions, although several common natural carboxylates (acetate, lactate, tartrate and citrate) have jerkily been used. 

The reaction of supported acrylic esters as 0.85 M solutions in an ionic liquid solvent such as n-butyltrimethylammonium or ethylmethylimidazolium triflimide ([BuMe3N][NTf2] or [EMIM][NTf2]) with an excess of cyclopentadiene at room temperature goes to completion within 2 h. After removal of the excess diene by vrashing with ether, the cycloadducts are cleaved from the support by transesterification in boiling methanol in the presence of traces of HQ. Extraction with ether or bulb to bulb distillation under vacuum allows the isolation of the methyl esters of the adducts in excellent yields (80-90%) and purities (Scheme 5.5-32). No influence of either the nature of the solvent or the supporting salts on the isolated yields of the norbomene derivatives or the endo/exo selectivity was observed [11,21]. 

DesMarteau and coworkers reported the preparation, X-ray crystal structure and chemistry of trifluo-roethyliodonium salts 391 by the reaction of fluoroalkyliodo-bis(trifluoroacetates) 389 with benzene and triflimide acid (390) (Scheme 2.113) [68,531,532], The structure of trifluoroethyl(phenyl)iodonium salt 391 (n = 1) was established by a single-crystal X-ray analysis [68], In contrast to fluoroalkyliodonium triflates 383, compounds 391 are stable to water and can be used as reagents for fluoroalkylation reactions in aqueous media. 

Reaction of Tf20 with Amines. The reaction of 1 equiv of Tf20 in CH2CI2 and EIbN with amines (or their salts) affords trifluoromethanesulfonamides (triflamides) in good yields. If 2 equiv of Tf20 are used, triflimides are formed. The triflamides are soluble in alkali and readily alkylated to triflimides (eq 7). ... 

Recently, Johnston and coworkers reported an impressive application of catalysis by the amidinium salts in an enantioselective iodolactonization reaction (Scheme 10.62) [162]. While the free bases were effective in catalyzing the reaction, higher enantioselectivities were obtained with the mono-protonated salts. Additionally, the authors discovered a high dependence of enantioselectivity on the nature of the achiral counter-ion, and among the anions tested the triflimidate anion was found to be the best in terms of both yield and enantioselection. With 5 mol% of the catalyst 64 HNTf2, the iodolactonization products were obtained in high yields (up to 99%) and excellent enantioselectivities (up to 98% ee). 

Diels-Alder reactions 47 triethoxysilyl acetylene 395 triethylamine (TEA) 721 triflate salts 1095 triflimides 436... 

Yu developed a similar method of Pd-mediated directed electrophilic fluorination of C-H bonds using iV-benzyl triflimide derivatives. Key to the success of Yu s chemistry is the use of 2,4,6-trimethylpyridinium fluoride as the triflate salt, which was identified through a screen of fluorinating agents. 

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