While the stabilization of cationic centers by alpha cyclopropyl groups has been verified in many instances [2,31, to the best of our knowledge nothing is known about the influenceof cyclopropyl groups, as substituents, on the reaction mechanism of multiple bonds. The α-cyclopropylcarbonium ions 141 that may be formed are capable of rearrangement, thus providing additional information as to a polar or a more concerted mechanism of cycloaddition
