Tandem Enyne Allene-Radical Cyclization via Base-Catalyzed Isomerization of Enediyne Sulfones.

Abstract Enediyne sulfones 12–16 undergo a base-catalyzed isomerization to the corresponding enyne allenes followed by a tandem enyne allene-radical cyclization at 37 °C to provide 2,3-dihydrobenz[ e ]indenes 17–21 in good yields.