3-Methyl-cyclohexenone 4 spiroannulates with 1, 4-dibromobutane in NaNH2/NH3 or t-BuOK/benzene to afford not only the main monospiro compounds 5a and 5b but also the dispiro compounds 6a and 6b. The title compound 11 was synthesized from 5 through the following steps: Catalytic hydrogenation of the spiro olefinic compounds, addition of trimethylsilycyanide to the carbonyl group, hydrolysis of the siloxyl ether, dehydration of the cyanohydrin and hydrolysis of the cyano group.