Reactions of 4,9-dibromo-1,6-dioxaspiro[4.4]nona-3,8-dien-2,7-dione (I) and 3,7-dibromo-1,6- dioxaspiro[4.4]nona-3,8-dien-2,7-dione (II) with nucleophiles yielding spirolactones IIIa-IIIg are described. The ring opening reactions of spirobilactones are discussed.