Synthesis of indolo[2,1-a]isoquinoline derivatives via visible-light-induced radical cascade cyclization reactions.

We describe a photocatalyzed transformation for the synthesis of the indolo[2,1-a]isoquinoline core structure. This redox neutral reaction features mild reaction conditions and exceptional functional group tolerance. A series of valuable indolo[2,1-a]isoquinoline derivatives bearing various functional groups were synthesized using this method in good to excellent yields.