Ag I /TMG‐Promoted Cascade Reaction of Propargyl Alcohols, Carbon Dioxide, and 2‐Aminoethanols to 2‐Oxazolidinones

Chemical valorization of CO 2 to access various value‐added compounds has been a long‐term and challenging objective from the viewpoint of sustainable chemistry. Herein, a one‐pot three‐component reaction of terminal propargyl alcohols, CO 2 , and 2‐aminoethanols was developed for the synthesis of 2‐oxazolidinones and an equal amount of α‐hydroxyl ketones promoted by Ag 2 O/TMG (1,1,3,3‐tetramethylguanidine) with a TON (turnover number) of up to 1260. By addition of terminal propargyl alcohol, the thermodynamic disadvantage of the conventional 2‐aminoethanol/CO 2 coupling was ameliorated. Mechanistic investigations including control experiments, DFT calculation, kinetic and NMR studies suggest that the reaction proceeds through a cascade pathway and TMG could activate propargyl alcohol and 2‐aminoethanol through the formation of hydrogen bonds and also activate CO 2 .