[lutesium]

How can a trifloromethyl group be synthesised!!! By the action of PF3 on a Carbon that's attached to the benzene ring??? But if the F is not a such good nucleophile why is this reaction so vigorous???

[Kryolith]

A modern way to synthesize a CF₃-substituted arene from ArI is the reaction with
Me₃SiCF₃ + KF + CuI (solvent DMF/N-methylpyrrolidone 1:1) at 25 °C

Or are you interessted in a "classical" way?

[lutesium]

Yes I do! But something such toxic as PF3 is not something that you can use inside a laboratory (Its like CO - a hemoglobine poison) so meeasuring its weight and putting it into a dropping funnel and then washing the glassware could be really hard!!! I don't have personal experience with the substance but these are just guesses!!!

What's the classical way that you've mentioned???

Thanks!!!

[Kryolith]

The method I mentioned above is perhaps one of the easiest, as it doesn't use HF or other "dangerous" fluoro compounds. Most reactions use harmful substances and the handling is nasty, I guess there's no chance to avoid this.

I just found the following references: You can convert carboxy groups with HF/SF₄ into CF₃-groups:

W. R. Hasek, W. C. Smith, V. A. Engelhardt, J. Am. Chem. Soc. 1960, 82, 543 – 551;
M. S. Raasch, J. Org. Chem. 1962, 27, 1406 – 1409;
D. G. Martin, F. Kagan, J. Org. Chem. 1962, 27, 3164 – 3168;
M. P. Mertens, S. E. Saheb, J. Heterocycl. Chem. 1965, 2, 491 – 491;
Y. Kobayashi, I. Kumadaki, S. Taguchi, Chem. Pharm. Bull. 1969, 17, 2335 – 2339.