Visible-Light-Mediated Oxidation of 1-Benzyl-3,4-dihydroisoquinolines with Dioxygen: A Switchable Synthesis of 1-Benzoylisoquinolines and 1-Benzoyl-3,4-dihydroisoquinolines

Abstract A visible-light-mediated metal-free oxidation of 1-benzyl-3,4-dihydroisoquinolines (1-BnDHIQs) for the switchable preparation of a wide range of 1-benzoylisoquinolines (BzIQs) and 1-benzoyl-3,4-dihydroisoquinolines (BzDHIQs) is realized using dioxygen as the oxidant. This protocol provides a facile route for the efficient synthesis of isoquinoline alkaloids. Mechanistic investigations suggest that a radical pathway and an ionic pathway may exist simultaneously, with both pathways proceeding via a common key peroxide intermediate to give the oxidized products.