Visible light promoted photoredox C(sp3)–H bond functionalization of tetrahydroisoquinolines in flow

Abstract

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.