CO₂-Mediated Rearrangement of Propargyl Alcohols

Significance

The silver-catalyzed rearrangement of propargyl alcohols yields α,β-unsaturated ­ketones in good yield with moderate diastereo­selectivity in some cases. The reaction is mediated by carbon dioxide and is proposed to proceed through a Meyer-Schuster reaction pathway. The solvent plays an important role in controlling the reaction pathway. The use of formamide gave the best results, proceeding through the [3,3]-sigma­tropic pathway, whereas toluene gave the cyclic carbonates.