(2 + 2 + 1)-Cyclization of Glycine Derivatives with Alkenes and CO₂

A highly atom-economic (2 + 2 + 1)-cyclization of glycine derivatives with alkenes and CO₂ facilitated by visible light catalysis is described. A range of multisubstituted pyrrolidones were synthesized under simple and mild reaction conditions. A reasonable mechanism involving redox-neutral radical-polar crossover is proposed.