Organophotocatalytic Intramolecular Formal Enyne‐Metathesis – An Alternative to Transition‐Metal Catalysis

Abstract A new approach to access 1,3‐diene derived quinolinone compounds has been realized using a mild reaction protocol employing a metal free catalyst (1,2,3,5‐tetrakis(carbazol‐9‐yl)‐4,6‐dicyanobenzene) (4CzIPN), blue LED as activation source, and benefits from a sustainable solvent dimethylcarbonate (DMC). The mechanism is postulated as an amide‐tethered enyne intramolecular [2+2]‐photocatalyzed cycloaddition‐retrocycloaddition sequence, proceeding via a cyclobutene intermediate species. The methodology offers an efficient route towards decorated 1,3‐diene products.