A-Benzyl Triflamide

Preparative Methods triflic anhydride (1 equiv) in dichloro-methane is added slowly to a stirred solution of benzylamine (1 equiv) in dichloromethane at 0 °C. After 1 h at 20 °C, the solution is washed with 10% HCl and water then dried (Na2S04) and evaporated to give ca. 90% of )V-benzyl triflamide as a colorless solid. Crystallization from CHCls-hexane secures the pure product, 5h (CDCI3) 7.26 (5H, s), 5.23 (lH,s), and 4.37 (2H, s). 

Handling, Storage, and Precaution the conqiound is a stable solid no hazards associated with its handling have been reported. Fluoromethanesulfonamides, in general, are known to possess herbicidal and anti-inflammatory properties. 

Gabriel Synthesis of Amines. )V-Benzyltriflamide was originally introduced as a new nitrogen source for the Gabriel synthesis of amines. Based on its pKa of 6.8 in 67% DMF-water and a gas phase acidity of AGacid = 318.8, due to the powerful electron-withdrawing effect of the triflate function, it was reasoned that a weak base should be sufficient to induce the necessary A deprotonation. Typical conditions (eq 1) for W alkylation 

Deprotection can be achieved in a number of ways, with lithium aluminium hydride seemingly being the reagent of choice to selectively remove the triflate group (eq 3). Yields are excellent, at least with simple substrates. This is in contrast to the removal of triflates from primary amine derivatives, when Red-A1 is the preferred reagent, as LiAlH4 forms stable salts with such reactants. 

The leaving group ability of a benzyltriflamide group is shown in an example of the use of -tosylethylamine as a reagent for the protection of secondary amides and carbamates (eq 6). While hardly an alternative preparation of the benzyltriflamide product, this does illustrate well the potential of a -tosylethyl group as an amine protecting function. 

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