A method for the preparation of an unique type of hyrocarbons, namely, bismethylene derivatives of linear triangulanes, has been developed, and the syntheses of 1, 4- bismethylenespiropentane, 1, 5-bismethylenedispiro [2.0. 2.1] heptanes, and 1, 6- bismethylenetrispiro [2.0. 0.2. 1.1] nonanes were realized.