Trifluoromethyl sulfones

Alkynyl trifluoromethyl sulfones add dimethylformamide and dimethylsul-foxide to give products in good yields The consistent stereospeciticity of the reaction syn addition product only) suggests that an unstable [2+2] cycloaddition intermediate is initially formed [J4] (equation 12). 

When the reaction between a-trifluoromethyl sulfone 286 and paraformaldehyde was carried out in the presence of potassium carbonate, the vinyl sulfone was obtained quantitatively upon elimination of triflate anion368. Such a deacylative methylenation was observed in the reaction between /J-ketosulfones 287 and 288 and paraformaldehyde3 69 3 71. 

A long series of studies of aromatic nucleophilic substitution included the kinetics of reactions of l-chloro-2,4-bis(trifluoromethylsulfonyl)benzene, 3-nitro-4-chlorophenyl trifluoromethyl sulfone and 2-chlorophenyl trifluoromethyl sulfone with sodium methox-ide or ammonia in methanol . The SO2CF3 group was found to have an enormous accelerating effect, in accord with the value of 1.65, based on the dissociation of anilinium ion. Further examples of the promotion of nucleophilic aromatic substitution by fluoro-substituted sulfonyl groups are given by Yagupol skii and coworkers . 

Scheme 3.3 Generation of [CI(dppe)2Ru=(C)4HPh]+ by protonation of a phenylbutadiynyl complex with trifluoromethyl sulfonic acid.

This was followed by titration with 0. IN trifluoromethyl sulfonic acid, and the end-point was detected with the use of a glass Ag/AgCl combination electrode [80]. 

Fluorine atoms in electron-deficient benzene derivatives, such as l-fluoro-2-nitroben-zene,149-150 l-fluoro-4-nitrobenzene.151 153 2-fluorobenzaldchyde,154"156 2-fluoroaceto-phenone,155156 4-fluoroacetophenonc,157 2-fluorobenzophenone.156 2- and 4-fluorobenzoni-trile,158 and 4-fluorophenyl trifluoromethyl sulfone,152,159 are easily substituted by N-nucleophiles. Even fluorine in electron-deficient sandwich complexes, such as tricarbonyl(t/6-fluoro-benzene)chromium (3), is substituted by amines.160161... 

The trifluoromethanesulfonyl (triflyl group) is one of the strongest electron-withdrawing groups and therefore is a versatile functionality for organic synthesis Trifluoromethyl sulfones have been prepared by using an electrophilic tnflyl source such as triflic anhydride or by displacing primary halides with a inflate salt... 

It has also been possible to prepare extremely stable triphenylphosphonium (trifluoromethanesulfonyl)methylide from chloromethyl trifluoromethyl sulfone and triphenylphosphine [6S] (equation 60)... 

PEG 400 polyethylene glycol, H-(OCH2CH2 )nOH [n = 8-9]. MA2 methyloctyl-2-dimethyl-butanamide. FS-13 phenyl trifluoromethyl sulfone. 

Trimethyl(trifluoromcthyl)siIanc is easily fluorodesilylated by tris(dimethyIamino)suIfonium difluorotrimethylsilicate [TASF(Me)], tetrabutylammonium fluoride, or tris(diethylamino) (methylamino)phosphonium hydrogen difluoride and, if arenesiilfonyl fluorides are used to trap the trifluoromethyl anion, trifluoromethyl sulfones are formed in high yield. Trisfdiethyl-amino)(methylamino)phosphonium phenolate is also an effective catalyst for this reaction, but TASF(Me) is favored as it can achieve the quantitative transformation of ArSOjF into aryl trifluoromethyl sulfones. ... 

Another convenient one-pot and high-yielding procedure for the preparation of aryl trifluoromethyl sulfones 37 from readily available arenesulfonyl fluorides and trimethylftrifluo-romethyl)silanc or -stannane, catalyzed by soluble nucleophilic agents such as tetrabutylammonium fluoride, tris(diethylamino)(methylamino)phosphonium hydrogen difluoride, tris-(diethylamino)(methylamino)phosphonium phenolate, and tris(dimethylamino)sulfonium di-fluorotrimcthylsilicate, has been reported.77... 

N ucleophilic substitution of s-trifluoromethylated sulfonates in the presence of a metal fluoride (functioning as a base) proceeds with complete inversion of the configuration.6... 

Carboxamides (e.g., 15) add to alkynyl trifluoromethyl sulfones such as 14 in good yield.71... 

N-trifluoromethyl sulfonic acid. The end-point was detected with use of glass Ag/AgCl combination electrode. Results compared well with those obtained using perchloric acid as titrant. The coefficient of variation were <0.42% and recoveries were >99%. 

CYCLOPENTENONES Boron trifluoride etherate. Copper(I) trifluoromethyl-sulfonate. 5,5-Dimethoxy-l,2,3,4-tetra-chlorocyclopentadiene. l-(Dimethyl-amino)-3-pentenotrile. Methanesulfonic acid. Phosphoric acid-Formic acid. Tetrakis(triphenylphosphine)palladium. 

Cu-diimine macrocycle compounds (31) are formed by Jaeger template condensations of diamines with acyl-substituted /3-keto imines (30) (Scheme 9). The acyl substituents on the macrocycles are labile and undergo a variety of reactions. Reaction with trifluoromethyl sulfonate produces reactive methoxy ethylidene diimine compounds (32), which react with amines to form saddle-shaped cyclidenes. With bulky substituents these compounds have a hydrophobic void above the metal ion which can accommodate a guest molecule, an effect enhanced when the... 

Scheme 2.178 Conversion of sulfonyl and sulfinyl halides to the corresponding trifluoromethyl sulfones and sulfoxides by nucleophilic trifluoromethylation [38].

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