Abstract: To investigate the stereochemical influence of a cyclopropyl group on carbonium ion formation in a homoallylic position, the four stereoisomers (Le., exo-anti, exo-syn, endo- anti, and endo-syn) of tricyclo [3.2. 1. 02r4]-octan-8-01 were synthesized and their p- nitrobenzoates (p-NB) or p-bromobenzenesulfonates (brosylates) were solvolyzed. Reaction of 5, 5-dimethoxy-l, 2, 3, 4-tetrachlorocyclopentadiene with cyclopropene gave the endo ...