A transition metal- and photosensitizer-free approach for site-selective (hetero)arylation of polychlorinated heteroarenes.

We have developed an effective photochemical method for site-selective (hetero)arylation of polychlorinated heteroarenes. This approach eliminates the need for transition metal catalysts and photosensitizers by relying on in situ formation of unconventional electron donor-acceptor (EDA) complexes between two substrates and a basic additive. Our protocol yields chlorine-containing biaryl heterocyclic compounds with high levels of site-selectivity, which are of significant importance in both synthetic and medicinal chemistry.