An intramolecular Pauson-Khandreaction of various 3-alkynyl-1-alkylidenecyclic compounds was performed to give the corresponding [5.n.1.0 1 , 5 ] tricyclic compounds (n = 2-4). A facile construction of the core structure in cedrene terpenoids was also investigated in detail and formal total synthesis of α- and β-cedrenes was accomplished.