Condensed-Phase, Halogen-Bonded CF3I and C2F5I Adducts for Perfluoroalkylation Reactions

An old reagent for trifluoromethylation turned user-friendly.

It is a pity that they do not pay us to review papers of whateverfluorination, because we would be doing some money. Here we have a short paper by Ritter et al. (Harvard University, MA, USA), describing how they have taken CF3I and C2F5I, and by mixing with tetramethylguanidine (TMG) have turned those nasty reagents into something that can be properly and confortably measured and used in a reaction. Believe me, we have used the CF3I in its original form, and it is a real pain in the posterior to work with it. Nobody in med chem likes to work with small gas cylinders, and just calculating how much reagent you are using is a challenge.

So this new reagent could be really useful. It is cheap and commercially available (Sigma-Aldrich). However, the paper does not give many details about scope: just 15 examples, most of them with substituted phenyl rings and only four heterocycles, all pyrimidines (and coming from the same intermediate). According to our experience, if it works more or less the same as the old CF3I it will have many uses.

Halogen Bonding

Angew. Chem. Int. Ed. 2015, Article Online.
See: 10.1002/anie.201410954