Photocatalyzed alkylative cyclization of 2-isocyanobiphenyls with unactivated alkyl iodides

We herein report the first photocatalyzed radical cascade cyclization of 2-isocyanobiaryls with unactivated alkyl iodides. This simple protocol operates under mild reaction conditions and affords 6-alkyl phenanthridines in good yields. To elucidate the reaction mechanism, Stern-Volmer quenching studies were carried out and these studies revealed that the photocatalyst is not directly involved in a single electron transfer process with the alkyl iodide. Photocatalyzed radical cascade cyclization of 2-isocyanobiaryls with unactivated alkyl iodides was developed. This protocol operates under mild conditions and tolerates a variety of functional groups affording 6-alkyl phenanthridines in good yields.