Photocatalytic Electrocyclization for the Synthesis of Dihydrophenanthrenes

Abstract A visible light induced electrocyclization for synthesizing dihydrophenathrenes is reported. The readily available organic photocatalyst 4‐CzIPN enables α‐addition to enones in good yield (up to 95 %). This 6π‐electrocyclization is proposed to proceed through a photosensitization pathway and it avoids the use of high energy UV light.