Trifiuoromethanesulfonic anhydride

Diaryl sulfones can be formed by treatment of aromatic compounds with aryl sulfonyl chlorides and a Friedel-Crafts catalyst.167 This reaction is analogous to Friedel-Crafts acylation with carboxylic acid halides (1-14). In a better procedure, the aromatic compound is treated with an aryl sulfonic acid and P205 in polyphosphoric acid.168 Still another method uses an arylsulfonic trifiuoromethanesulfonic anhydride ArS020S02CF3 (generated in situ from ArS02Br and CF3S03Ag) without a catalyst.169... 

The C-4 acids (183 and 184) have also been subjected to borane reduction conditions to afford alcohol 195 in 23-50% yield or 64% yield as the C-8 epimeric mixture (195 and 196, Scheme 29) [34, 49, 64]. The C-8 alcohol epimers 195 and 196 have been treated separately as a common intermediate for a number of C-4 derivatives including esters, ethers, and amines [34,49, 64]. Alcohols 195 and 196 was subjected to DCC, DMAP, and desired acid chloride or carboxylic acid in CH2CI2 affording ester analogs in 50-92% yield [64]. Esters prepared include alkyl, aryl, and fluorenylmethyloxycarbonyl (Fmoc) protected amino acid derivatives (197 and 198) [64]. Ethers were prepared with various alkyl halides and Ag20 in CH3CN at 40 °C. Alkyl, aUyl, and benzyl ethers were prepared in 45-80% yield (199 and 200) [34,64]. Alcohols 195 and 196 were then activated to the trifiates and displaced by a variety of amines by treatment with trifiuoromethanesulfonic anhydride and desired amine in 22% - quantitative yield over two steps (201 and 202)... 

Cationic polymerization of THF provided the first thoroughly studied example of polymerization with reversible deactivation of active species. In the polymerization initiated by trifiuoromethanesulfonic acid (or its derivatives such as anhydride or ester), the active species are involved in the following equilibria (Scheme 29). " ... 

---