Radical Cyclization in Heterocycle Synthesis. Part 10: A Concise Synthesis of (−)-Kainic Acid via Sulfanyl Radical Addition–Cyclization–Elimination Reaction

Sulfanyl radical addition–cyclization–elimination of diallylamines in the presence of thiophenol and AIBN gave the 2,3,4-trisubstituted pyrrolidine in high yield. This reaction was extended to a radical cyclization using a catalytic amount of thiophenol. A successful application was demonstrated by the asymmetric synthesis of (−)-kainic acid.