Benzylic Fluorination of Aza-Heterocycles Induced by Single-Electron Transfer to Selectfluor

Article abstract of DOI:10.1002/anie.201801280

A selective and mild method for the benzylic fluorination of aromatic azaheterocycles with Selectfluor is described. These reactions take place by a previously unreported mechanism, in which electron transfer from the heterocyclic substrate to the electrophilic fluorinating agent Selectfluor eventually yields a benzylic radical, thus leading to the desired C?F bond formation. This mechanism enables high intra- and intermolecular selectivity for aza-heterocycles over other benzylic components with similar C?H bond-dissociation energies.