Trifluoromethyl transfer from

The bond between the trifluoromethyl group and boron is difficult to form Preparation of trifluoromethyl aminohoranes was successfully achieved by transfer of trifluoromethyl group from reagent 2, which was prepared in situ [107] (equation 85)... 

Of course a bridged system must be involved, at least in the transition state, between boron and carbon in the decomposition of diazonium salts (Figure 4.30) and, indeed, transfer from trifluoromethyl has been observed [77] (Figure 4.30). 

Burton and co-workers, as part of a series of ground-breaking studies on fluorinated organometallic systems [14], have established that trifluoromethyl derivatives may be obtained by reaction of halofluoromethanes with copper and other metals. The process involves electron transfer from the metal, with subsequent loss of halogen to form difluorocarbene which, in turn, generates very active fluoride ion by reaction with the solvent. The full process is indicated in Figure 10.60. 

Reactions of carbonyl compounds and imines. The salt 4 obtained from reaction of cinchonine with m-xylylene dibromide is shown to promote enantioselective transfer of the trifluoromethyl group from Me3SiCF3 to aryl ketones Also obtained from quinidine the salt containing a trifluorobenzyl group (5) promotes the condensation of chloromethyl phenyl sulfones with ArCFlO to give benzenesulfonyl epoxides ... 

It is worth noting that the perfluorovinyl group can be transferred from mercury to arsenic whereas the trifluoromethyl group cannot 122,123). 

The catalytic enantio-selective addition of zinc alkynylides to various trifluo-romethyl ketones with selectivities that surpass 94% ee has been reported. By using 0 pseudoenantiomeric cinchona alkaloids as chiral ligands (e.g. 22), both enantiomers of the trifluoromethylated products were synthesized. The first experimental and computational evidence has been provided in support of alkynyl group transfer from an intermediate complex formed by transmetallation reaction between the alkynylide and the titanium catalyst. 

Chen MJ, Fremgen DE, Rathke JW (1998) Oxygen atom transfer from p-oxo-bis[l,4,8,11,15,18,22,25-octakis(trifluoromethyl)phthalocyanmato]diiron(lll) evidence for an Fe =0 intermediate. J Porphyrins Phthalocyanines 2 473 82... 

The carbene transfer from bis(trifluoromethyl)diazomethane to octacarbonyl dicobalt gives at room temperature in 28 days the p -bis(trifluoromethyl)methylene complex IS that was isolated in 54% yield (reaction 8.33) [64,65]. 

Alkylation. Ben2otrifluoride can also be alkylated, eg, chloromethyl methyl ether—chlorosulfonic acid forms 3-(trifluoromethyl)ben2yl chloride [705-29-3] (303,304), which can also be made from / -xylene by a chlorination—fluorination sequence (305). Exchange cyanation of this product in the presence of phase-transfer catalysts gives 3-(trifluoromethylphenyl)acetonitrile [2338-76-3] (304,305), a key intermediate to the herbicides flurtamone... 

Recently developed trifluoromethylatmg agents capable of transferring the trifluoromethyl group as a cation to strongly nucleophilic compounds such as carbanions and sulfur and phosphorus nucleophiles are prepared from o-biphenyl trifluoromethyl sulfoxide [164] and are shown in equation 141... 

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