Facile synthesis of carbamoylated benzimidazo[2,1-a]isoquinolin-6(5H)-ones via radical cascade cyclization under metal-free conditions

A highly efficient synthesis of carbamoylated benzimidazo[2,1-a]isoquinolin-6(5H)-ones using 2-arylbenzoimidazoles and oxamic acids was developed. This strategy tolerated various substrates as the starting materials to generate the corresponding products in good yields under metal-free conditions.