In the presence of 5mol% of tin (IV) triflimidate, a cyclization reaction of epoxyesters to δ- hydroxy-γ-lactones proceeding in 46–98% yields without additives, ligands, or co-catalysts was observed. The cyclization to five-membered rings is greatly favored compared to the possible six-membered rings formation and is probably under the control of a Thorpe–Ingold type effect.