Intermolecular [2+2+1] Carbonylative Cycloaddition of Aldehydes with Alkynes,and Subsequent Oxidation to γ‐Hydroxybutenolides by a Supported Ruthenium Catalyst

Intermolecular 2+2+1] carbonylative cycloaddition of aldehydes with alkynes and subsequent oxidation to γ‐hydroxybutenolides is achieved using a supported ruthenium catalyst. A ceria‐supported ruthenium catalyst promotes the reaction efficiently, even with an ambient pressure of CO or without external CO, thus giving the corresponding γ‐hydroxybutenolide derivatives in good to high yields. Moreover this catalyst can be reused with no loss of activity.