A catalytic fluoride-rebound mechanism for C(sp ³ )-CF ₃ bond formation

Trifluoromethylation via broken C-F bonds Trifluoromethyl substituents are widely used in pharmaceutical research to tune the properties of drug candidates. Generally, they are introduced intact through the formation of carbon-carbon bonds. Levin et al. discovered an unusual alternative mechanism, in which borane abstracts fluoride from the CF 3 group in a gold complex. The activated CF 2 fragment can then bond to a wide variety of other carbon substituents added to the same gold center. Return of the fluoride liberates a trifluoromethylated compound from the metal. This mechanism could be useful for the introduction of radioactive fluoride substituents for positron emission tomography applications. Science , this issue p. 1272