Visible-light-driven cascade radical cyclization toward the synthesis of α-carbonyl alkyl-substituted benzimidazo[2,1- a ]isoquinolin-6(5 H )-one derivatives.

A visible-light-driven cascade radical cyclization process of N -methacryloyl-2-phenylbenzimidazole has been established with α-carbonyl alkyl bromide. This protocol provides an efficient and practical method for the synthesis of various α-carbonyl alkyl-substituted benzimidazo[2,1- α ]isoquinolin-6(5 H )-ones in outstanding yields, mild reaction conditions and excellent functional group tolerance.