Preparation and characterization of a novel silica–KF composite and facile fluorination of aromatic substrates

Abstract

A novel silica–KF reagent prepared by hydrolyzing tetraethyl orthosilicate in the presence of KF for fluorination of activated aromatic compounds has been reported. The reagent, as characterized by techniques such as SEM-EDX, XRD and IR spectroscopy, is shown to have potassium cations entrapped inside the silica matrix whereas fluoride anions remain on the surface. Reaction of activated chlorinated aromatic substrates with this silica–KF leads to formation of Meisenheimer complex, either in situ or isolable, finally resulting in regioselective fluorinated aromatics.