Visible light promoted photoredox C(sp)-H bond functionalization of tetrahydroisoquinolines in flow

A merger of organocatalysis and visible light photoredox catalysis performed in flow allowed access to a wide range of functionalized N -aryl-substituted tetrahydroisoquinolines (THIQs) in a formal C-H oxidation/Mannich reaction. Strecker type functionalization and copper-catalyzed alkynylation of several N -aryl-substituted THIQs were also successfully performed in flow, giving valuable products with high efficiencies. The use of custom-made porous polymeric type microreactors proved to be crucial regarding the C-H oxidation step and overall reaction performance. Visible light promoted C(sp 3 )-H functionalization of N -aryl-protected tetrahydroisoquinolines under microflow conditions with various coupling partners in excellent yields and efficiencies.