Carbon dioxide-mediated catalytic rearrangement of propargyl alcohols into α,β-unsaturated ketones

In the presence of a catalytic amount of a silver salt with DBU under a CO2 atmosphere, various tertiary and secondary propargyl alcohols were efficiently converted into the corresponding M,P-unsaturated carbonyl compounds in high yield. An isotopic experiment using (CO2)-O-18 revealed that carbon dioxide mediated the rearrangement via an intramolecular nucleophilic attack on the alkyne activated by the silver catalyst.