Modular synthesis of phenanthridine derivatives by oxidative cyclization of 2-isocyanobiphenyls with organoboron reagents.

Where HAS you been? A manganese-mediated annulation of 2-isocyanobiaryls with organoboronic acids is developed for the synthesis of a broad range of phenanthridine derivatives. Mechanistic studies indicate that the reaction proceeds by the intramolecular homolytic aromatic substitution (HAS) of an imidoyl radical intermediate.