Dialkylation of cyclohexanone and spiro [5, 5] undecanones with 1, 5-dibromopentane or 1, 1-bis (2-bromo-ethyl) cyclohexane (IV) gave seven di-, tri-and tetraspiro ketones (V–XI), which embody four new polyspiro ring systems. Four polyspiro ketones could be reduced according to the Wolff-Kishner method giving three new polyspiro hydrocarbons (XXI— XXIII), while reduction with lithium aluminium hydride gave polyspiro alcohols (XXIV and ...
[Scheffold, Rolf; Dike, Meera; Dike, Sunneel; Herold, Thomas; Walder, Lorenz Journal of the American Chemical Society, 1980 , vol. 102, # 10 p. 3642 - 3644]