Amines trifluoromethanesulfonic acid

Trifluoromethanesulfonic acid anhydride, bp 84°C, is prepared by refluxing the acid over an excess of phosphorous pentoxide (18,26). The anhydride reacts instantaneously with ammonia or amines to form trifluoromethanesulfonamides. The anhydride reacts with most polar organic solvents. 

Amides of trifluoromethanesulfonic acid (triflamides) can be prepared by the reaction of the corresponding amines with triflic anhydnde The most applicable m organic synthesis are N-phenyltnflamides, which can be used as mild and selective inflating reagents [UO, III]... 

Further side-chain chemistry can be carried out either at one of the side chains attached to the five-membered ring [228-232] or at the pyrrolidine nitrogen [215, 224, 231, 233-239], For example, upon heahng 3-triphenylmethyloxazolidin-5-one (210) at reflux for 16 h with Cjq in equimolar amounts, 211 can be isolated in 39% yield [204], Subsequent treatment of 211 with trifluoromethanesulfonic acid, then with pyridine and dansyl chloride (DnsCl) yields the dansyl pyrrolidine derivative 213 in 76% yield (Scheme 4.35). The amine 212 is an intermediate in this reachon. 

All these electrolytes are neutral in Bronsted acid-base properties. Although rather exceptional, an acid, a base, or a pH buffer may be added to the supporting electrolyte of neutral salts. The acid-base system to be selected depends on the purpose of the measurement. We often use trifluoromethanesulfonic acid (CF3S03F1) as a strong acid acetic acid, benzoic acid, or phenol as a weak acid an amine or pyridine as a weak base and tetraalkylammonium hydroxide (ILtNOH) as a strong base. Examples of buffer systems are the mixtures of picric acid and its R4N-salt and amines and their PlCl04-salts. Here, we should note that the acid-base reactions in aprotic solvents considerably differ from those in water, as discussed in Chapter 3. 

The electrophilic, aromatic substitution of electron-rich arenes with the electron-deficient azodicarboxylate BTCEAD is a powerful method for the introduction, in a single operation, of a masked hydrazine or amino group.3 4 Several activators can be used for this amination reaction ZnCl2,4 BF3-Et20,4 LiCIO.4,3 and here, trifluoromethanesulfonic acid.5 Trifluoromethanesulfonic acid dramatically increases the rate of the amination reaction and makes possible the use of this methodology with poorly reactive substrates. 

The trifluoromethanesulfonates have certain advantages over perchlorates (nonexplosive) and tetrafluoroborates (even less reactive toward oxidizing agents) [447]. The tetraalky-lammonium trifluoromethanesulfonates are just as soluble or more soluble in the commonly used organic solvents than the corresponding perchlorates or fluoroborates. They can be prepared either by metathesis or by alkylation of a tertiary amine by an ester of trifluoromethanesulfonic acid. 

The amidation of a-hydroxyallylic phosphonates (2IS) with nitriles in the presence of trifluoromethanesulfonic acid proceeds with high ( )-stereoselectivity and with moderate to good yields of (216) [R = H, R = Me or Ph R = Me, = Ph R R = (CH2)n, n = 2-4 R = Me or Ph]. Mannich reactions between diethoxyphosphinoylacetic acid, a primary amine, and formaldehyde, have been used for the preparation of (217). ... 

The acid-promoted intramolecular Schmidt reaction of azido-alkene 114 is featured in the formal synthesis of gephyrotoxin. Treatment of 114 with trifluoromethanesulfonic acid followed by L-Selectride reduction of the resultant iminium ions 115 and 116 generates a mixture of diastereomeric bromo-amines. The bromide is replaced with acetate ion, and the acetate is reduced to give alcohol 117, a known intermediate in the synthesis of gephyrotoxin. 

Aniline allowed to react at -78° with trifluoromethanesulfonic acid anhydride and triethylamine in methylene diloride -> N-phenyltriflamide. Y 97%. - The protective group can be removed by reduction. F. e. and triflating agent, also Gabriel-type synthesis of prim, amines from halides via triflamides, s. J. B. Hendrickson and R. Bergeron, Tetrah. Let. 1973, 3839. 

Takeuchi H, Adachi T, Nishiguchi H, Itou K, Koyama K (1993) Direct aromatic amination by azides reactions of hydrazoic acid and butyl azides with aromatic compounds in the presence of both trifluoromethanesulfonic acid and trifluoroacetic acid. J Chem Soc Perkin Trans 1 867-870... 

Borodkin GI, Elanov IR, Shubin VG (2009) Electrophilic amination of methylbenzenes with sodium azide in trifluoromethanesulfonic acid. Russ J Org Chem 45(6) 934-935... 

Maruoka also uhlized 3,3 -modified binaphthyl-derived chiral primary amine 21, in combination with trifluoromethanesulfonic acid (TfOH), as a catalyst for the Diels-Alder reachon of a-substituted a,P-unsaturated aldehydes with cyclopenta-diene, which afforded the corresponding cycloadducts possessing an all-carbon quaternary stereocenter with good to high stereoselectivity (Scheme 7.34) [58],... 

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