Visible light-mediated difluoromethylation/cyclization in batch and flow: scalable synthesis of CHF 2 -containing benzimidazo- and indolo[2,1- a ]isoquinolin-6(5 H )-ones.

We report here a practical and cost-effective method for the synthesis of CHF 2 -containing benzimidazo- and indolo[2,1, a ]-isoquinolin-6(5 H )-ones through a visible light-mediated difluoromethylation/cyclization cascade. The method, which affords functionalized multifused N-heterocyclic scaffolds in moderate to high yields under mild reaction conditions, is also easily scalable using low-cost 3D printed photoflow reactors.