Catalyst-Controlled Regiodivergent C–H Arylation Site of Fluorinated 2‑Arylpyridine Derivatives: Application to Luminescent Iridium(III) Complexes

Regiodivergent
C–H bond arylation of fluorinated 2-arylpyridines
and 2-arylquinolines has been developed. The use of Pd catalyst allows
functionalization of the C–H bond of the aryl flanked by two
fluorine atoms (most acidic position), while using Ru catalyst, the
arylation takes place on the aryl unit at the ortho position of the heterocycle. Both reaction conditions exhibit
a good functional group tolerance. The synthetically useful selectivity
observed with Pd catalyst was applied to design C^N ligands for the
preparation of luminescent cationic iridium­(III) complexes. The influence
of the incorporated aryl group onto the fluorinated phenyl unit and
the fluorine position patterns on the photophysical properties is
described.