Epoxidation of 3-ylidene derivatives (3, 4, 7 and 8) using alkaline hydrogen peroxide, and monoperoxyphthalic acid magnesium salt hexahydrate gave the corresponding new oxoindole-spiro-oxirane derivatives (5, 6, 9 and 10). The reaction of compound 10 with nucleophilic reagents was investigated. The resulting products depend on the type of spiro compound and/or the nucleophile used.