Intramolecular Pauson-Khand Reaction of 3-Alkynyl-1-Alkylidenecycles:A Convenient Synthesis of [5.n.1.0] Tricyclic Compounds

摘要

An intramolecular Pauson-Khand reaction of various 3-alkynyl-l-alkylidenecyclic compounds was performed to give the corresponding [5.n.l.0~(15)] 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 alpha- and beta-cedrenes was accomplished.