Modular Synthesis of Phenanthridine Derivatives by Oxidative Cyclization of 2-Isocyanobiphenyls with Organoboron Reagents


  • This work was supported, in part, by a Grant-in-Aid for Scientific Research on Innovative Areas of “Molecular Activation Directed toward Straightforward Synthesis” from MEXT (Japan). We thank Prof. Kei Ohkubo and Prof. Shunichi Fukuzumi for obtaining EPR spectra. We also thank the Instrumental Analysis Center of the Faculty of Engineering at Osaka University for their assistance with HRMS.


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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 (see scheme). Mechanistic studies indicate that the reaction proceeds by the intramolecular homolytic aromatic substitution (HAS) of an imidoyl radical intermediate.