Site-Selective Cross-Coupling of Dichlorinated Benzo-Fused Nitrogen-Heterocycles with Grignard Reagents

Site-selective cross-coupling of dihaloarenes constitutes a useful method for synthesis of multi-substituted arenes. In this paper, we report the site-selective cross-coupling of dichlorinated benzo-fused nitrogen-heterocycles having two chloro groups on the benzene ring. These dichlorinated heterocycles reacted with Grignard reagents in the presence of PdCl2(PCy3)2 at the positions ortho to the nitrogen-based substituents with high selectivities. A mechanism in which interaction between Lewis acidic Mg and Cl of the ortho position facilitates C–Cl bond cleavage is proposed.