Trifluoromethoxy group

An example of cleavage ol the sulfur-oxygen bond in trifluoromethane-sulfonic ester has been reported Tnfluororaethyl triflate reacts with neutral or anionic nucleophiles with elimination of carbonyl difluoride and formation of trifluoromethanesulfonyl fluoride [57] (equation 32) The mechanism of this reaction involves elimination of fluoride ion, which is a chain carrier in the substitution of fluorine for the trifluoromethoxy group... 

The methods that are known for introducing trifluoromethoxy groups into arenes are generally not effective. An interesting onc-pot O-alkylation of phenols followed by halogen exchange to form trifluoromethyl ethers 6 has been described227 (see also Houben-Weyl, Vol. E4, pp 626-627). 

In fluorinated agrochemicals, the difluoromethoxy group is less commonly encountered than the trifluoromethoxy group. The difluoromethoxy group is readily available from the reaction of a phenoxy group and difluorocarbene, generated from chlorodifluoromethane and a base (Fig. 27) [6,107-109]. 

TABLE 16. Isotropic coupling constants (gauss) and conformation for radicals containing a trifluoromethoxy group and analogues... 

Addition of Fluorine and a Trifluoromethoxy Group with Trifluoromethyl Hypofluorite... 

The strong electronegative trifluoromethyl group in trifluoromethyl hypofluorite stabilizes the hypofluorite function and activates the O —F bond for electrophilic reaction. Thus, trifluoromethyl hypofluorite undergoes addition to oletinic centers the trifluoromethoxy group often can be hydrolyzed to leave a monofluorinated product. 

Carcenac, Y., Tordeux, M., Wakselman, C. and Diter, P. (2006) Experimental determination of the conformational free energies (A values) of fluorinated substituents in cyclohexane by dynamic 19F NMR spectroscopy. Part 2. Extension to fluoromethyl, difluoromethyl,pentafluor oethyl, trifluoromethylthio and trifluoromethoxy groups. New J. Chem., 30, 447 -57. 

Perfluoroalkoxy groups and, especially, the trifluoromethoxy group, are commonly used as structural elements in pharmaceuticals (Section 4.5) and organic materials (Section 4.4). Aromatic and aliphatic perfluoroalkoxy groups are conveniently accessible via fluorodesulfuration chemistry (see also Section 2.1.5.4). Nevertheless, the technically important trifluoromethoxy arenes, in particular, are produced on a larger scale by a different method, based on chlorine-fluorine exchange with hydrofluoric acid [17] (Scheme 2.172). 

Aromatic chlorine can also be bioisosterically replaced by a trifluoromethoxy group, which serves as a kind of pseudohalogen [63] (Figure 4.20). 

The compound possess a trifluoromethoxy group that acidifies the N H binding in the amid moiety to improve the inhibitory properties. 

Castagnetti, E., Schlosser, M. (2002). The Trifluoromethoxy Group A Long-Range Electron-Withdrawing Substituent. Chemistry -A European Journal, 8(4), 799-804. 

The trifluoromethoxy group in aryl cannot be formed analogously to the methoxy group, by simple treatment of trifluorohalomethanes with alkoxides, so it has to be introduced or constructed by one of the following approaches (Fig. 5) ... 

On the basis of its electronic properties, which are close to those of a chlorine or a fluorine atom [70], the trifluoromethoxy group has been referred to as a super- [71] or a pseudo-halogen [72], The advantage of incorporating a trifluoromethoxy group into a molecule can be described in terms of its properties. The trifluoromethoxy group is... 

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