The synthesis of anticancer sulfonated indolo[2,1- a]isoquinoline and benzimidazo[2,1- a]isoquinolin-6(5 H)-ones derivatives via a free radical cascade pathway

A facile CuBr2 induced radical relay addition/cyclization of activated alkenes with substituted-thiosulfonates has been achieved, leading to a broad range of sulfonated indolo[2,1-a]isoquinolines and benzimidazo[2,1-a]isoquinolin-6(5H)-ones in moderate to good yields. In particular, some compounds exhibit bioactivity against cancer cell lines. This protocol shows advantages of low-cost, base-free, simple operation, and broad functional group tolerance.