Triflamide

An alternative to Gabriel synthesis is based on the alkylation of tnfluoro-acetamide [770, 777[ or Al-benzyl triflamide [772] in place of the classical phtalimide (equations 96 and 97). 

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]... 

A trifluoromethylsulfonamide can be prepared from a primary amine to allow monoalkylation of that amine. The triflamide is not stable to strong base, which causes elimination to an imine, but when used to protect an indole, it is cleaved with K2CO3 in refluxing methanol. ... 

An alternative to the use of pivalamides 66 is the lithiation of triflamides 67 catalyzed by naphthalene (4%) in the presence of different electrophiles at temperatures ranging between —78 and 0 °C, so after hydrolysis the expected products 20 were isolated (Scheme 26). ... 

Acyl triflamides are excellent acylating agents for alcohols and amines [52], Classical methods for carboxyl activation include formation of anhydrides, either homo- or mixed (e.g. phosphoryl, sulfonyl, etc.). Further activation is possible by adding 4-dimethylaminopyridine as catalyst [53], The active acylating agents are throught to be... 

A partially soluble polyallylscandium triflamide ditriflate 45 was prepared and used to catalyze a three-component coupling reaction.67 An aldehyde, an aromatic amine, and an alkene were mixed in the presence of the catalyst to afford tetrahydroquinolines (equation 17). The catalyst was recovered from the reaction mixtures by precipitation with hexane and could be recycled without loss of activity. Another polymer-supported scandium catalyst was prepared by treating Nafion with scandium chloride to afford the Nafion-scandium catalyst 46.68 This catalyst was used in allylation reactions of carbonyl compounds by tetraallyltin (equation 18). It could be easily recovered by filtration and reused without appreciable loss of activity. 

OH - —NTfCHj. Primary or secondary alcohols are converted to protected secondary amines by this triflamide under Mitsunobu conditions (triphenylphos-phine, diethyl azodicarboxylate) in 70-86% yield. The reaction proceeds with inversion, and is useful for preparation of optically active secondary amines. 

Table 6.44 Bis-triflamide-catalyzed Mukaiyama aldol reactions.

Acyclic C-N bonds of allyl or benzyl triflamides,51 pivalamides and carbamate derivatives9 can be reductively lithiated, as can N-benzyl benzotriazoles.72... 

Synthesis of 345 has been achieved (equation 221) by reaction of [18F]fluoride with the triflamide alcohol 342 or via the cyclic sulphamate 344. 

Diels-Alder Reactions. Reaction of the bis(triflamide) (2) with Diisobutylaluminum Hydride or Trimethylaluminum affords chiral Lewis acids that catalyze Diels-Alder reactions of acryloyl or crotonoyl derivatives with cyclopentadienes (eq 4). The aluminum complex must be crystallized before use to remove traces of trimethylaluminum. High diastereo- and enantioselectivities are achieved with as little as 0.1 equiv of the Lewis acid, and the chiral sulfonamide is recoverable. 

Paulechka YU, Blokhin AV, Kabo GJ et al. (2007) Thermodynamic properties and polymorphism of l-alkyl-3-methylimidazolium bis(triflamides). J Chem Thermodyn 39 866-877... 

The ytterbium salt was prepared from commercially available lithium triflamide (3M chemical company). A representative procedure is given below (Ref. 29)... 

Furthermore, the use of the electrophilic fluorinating reagent 11 to effect oxidative formation of C—F bonds in 8-methylquinoline (9) was reported [22], More recently, a versatile palladium-catalyzed ortho-fluorination of the triflamide-protected benzyla-mine 12 was disclosed, which also made use of electrophilic fluorinating reagents (Scheme 9.4) [23]. 

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