A Visible Light Photoredox Catalysed Radical Pictet-Spengler Reaction

Abstract

A methodology for a radical Pictet–Spengler reaction promoted by visible light photoredox catalysis is described. This strategy furnishes tetrahydroisoquinoline derivatives bearing electron poor and electron rich substituents. The reaction proceeds at room temperature and with excellent regioselectivity for the 6-endo intramolecular cyclisation. This radical approach provides a complementary method for the synthesis of the tetrahydroisoquinoline scaffold with substitution patterns inaccessible via established thermal transformations.