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 CO 2 atmosphere, various tertiary and secondary propargyl alcohols were efficiently converted into the corresponding α,β-unsaturated carbonyl compounds in high yield. An isotopic experiment using C 18 O 2 revealed that carbon dioxide mediated the rearrangement via an intramolecular nucleophilic attack on the alkyne activated by the silver catalyst.