Stereoselective synthesis of spiroannulated cyclopentenones by the Pauson–Khand reaction on carbohydrate derived enynes

The stereoselective synthesis of spiroannulated cyclopentenones by the Pauson–Khand reactions on hexose and pentose derived enynes was achieved under carbon monoxide free conditions using a stoichiometric quantity of Co2(CO)8. The cobalt complex of the alkyne was cleaved using dimethoxyethane–acetonitrile at 85 °C to furnish spiroannulated cyclopentenones in 75–94% yields.