Abstract: The acetolysis of 2-(A1-cyclobutenyl) ethyl tosylate gives 3-methylenecyclopentyl acetate, 2-methylenecyclopentyl acetate, 2-(A1-cyclobuteny1) ethyl acetate, 1- acetoxymethylcyclopentene, and 4-acetoxy-1-methylcyclo-pentene as products. Deuteriumlabeling experiments indicate that a symmetrical spiro [2.3] hexyl-2 cation is not the intermediate. The course of the reaction is discussed.