Pauson-Khand reaction (PKR) is a useful reaction for formation of cyclopentenones from alkyne-cobalt complex, which is obtained from alkynes and Co
2 (CO)
8, and alkenes by heating the mixture or by treating the mixture with amine
N-oxide at room temperature. Until now, there are many reports on PKR of both
endo-cyclic and acyclic olefins, however, only a few reports on
exo-olefins have appeared. Thus, the authors investigated intra- and inter-molecular PKR of
exo-olefins. The intramolecular reaction of cyclic and acyclic enynes bearing
exo-olefins was performed to give corresponding bi- and tri-cyclic compounds. Also, intermolecular PKR of
exo-cyclic olefins with alkynes furnished spiro-bicyclic compounds. Furthermore, the present methodology was developed to construct tricyclic skeleton of
Lycopodium alkaloid, magellanine family and formal total synthesis of magellanine was accomplished.
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