Visible Light Photocatalyzed Norrish Type II Reaction of Acrylamides for the Synthesis of β‐Lactams

Here, we present a strategy for the visible‐light‐catalyzed synthesis of β‐lactams based on the Norrish type II reaction. This protocol uses acetonitrile as solvent and commercially available photocatalyst to drive the reaction. Notably, various challenging substrate types reported in previous studies undergo conversion. DFT calculations further elucidate the reaction mechanism, while discussing the competitiveness between [2+2] cycloaddition and the Norrish II reaction.