From C1 to C2 : TMSCF3 as a Precursor for Pentafluoroethylation.

A highly efficient copper-mediated aromatic pentafluoroethylation method using TMSCF3 as the sole fluoroalkyl source is described. The reaction proceeds by a key C1 to C2 process, that is, the generation of CuCF3 from TMSCF3 , followed by a subsequent spontaneous transformation into CuC2 F5 . Various aryl iodides were pentafluoroethylated with the TMSCF3 -derived CuC2 F5 . This method represents the first practical and efficient method for pentafluoroethylation of aryl iodides using commercially available TMSCF3 as a pentafluoroethyl precursor.