Photoinduced Phosphinylation/Cyclization of 1,5‐Enenitriles for the Synthesis of Phosphinylated Pyrrolidine‐2,4‐diones

A metal‐free blue‐light‐induced radical cascade cyclization of N ‐tethered 1,5‐enenitriles with diarylphosphine oxides for the synthesis of phosphinylated pyrrolidine‐2,4‐diones is described. The transformation tolerates various functional groups and is scalable to gram scale. Radical‐trapping experiments confirm phosphorus‐centered‐radical‐mediated reactivity. Two unreported minor phosphorus‐containing products were detected by LCMS. This work provides a facile photochemical entry to phosphorus‐functionalized pyrrolidine‐2,4‐diones.