2-Methylene-or alkylidenecyclopropanyl ketones were easily prepared by the regioselective cyclopropanation of allenes or the reaction of methylene-/alkylidenecyclopropanyllithium with N, N-dimethyl carboxylic acid amides. Due to the presence of the exo-cyclic CC bond and the strained cyclopropane, their highly selective ring-opening cycloisomerization using PdCl2 (CH3CN) 2, NaI (or PdCl2 (CH3CN) 2+ NaI), and Pd (PPh3) 4 as catalysts provided ...