Cu I ‐Catalyzed Pentafluoroethylation of Aryl Iodides in the Presence of Tetrafluoroethylene and Cesium Fluoride: Determining the Route to the Key Pentafluoroethyl Cu I Intermediate

The Cu(I)‐catalyzed pentafluoroethylation of iodoarenes via the fluorocupration of tetrafluoroethylene (TFE) is disclosed. The active species, (phen)CuC 2 F 5 , was isolated and its molecular structure confirmed by a single‐crystal X‐ray diffraction analysis. The key to the successful suppression of the competing oligomerization of TFE is to refrain from stirring the reaction mixture. A mechanistic study clearly discarded the possibility that the catalytic reaction proceeds via a radical pathway.