Utilising Sodium‐Mediated Ferration for Regioselective Functionalisation of Fluoroarenes via C−H and C−F Bond Activations

Pairing iron bis(amide) Fe(HMDS)₂ with Na(HMDS) to form new sodium ferrate base [(dioxane)_0.5 ⋅NaFe(HMDS)₃ ] (1) enables regioselective mono and di-ferration (via direct Fe-H exchange) of a wide range of fluoroaromatic substrates under mild reaction conditions. Trapping of several ferrated intermediates has provided key insight into how synchronised Na/Fe cooperation operates in these transformations. Furthermore, using excess 1 at 80 °C switches on a remarkable cascade process inducing the collective twofold C-H/threefold C-F bond activations, where each C-H bond is transformed to a C-Fe bond whereas each C-F bond is transformed into a C-N bond.