AgI/TMG-Promoted Cascade Reaction of Propargyl Alcohols, Carbon Dioxide, and 2-Aminoethanols to 2-Oxazolidinones

Graphical Heterocycle promotion : An Ag 2 O/TMG (1,1,3,3-tetramethylguanidine) promoted substrate-driven and divergent route leads to a variety of heterocycles from propargyl alcohols, CO 2 , and 2-aminoethanols with turnover numbers up to 1260. The reaction proceeds through a cascade pathway with α-alkylidene cyclic carbonate as the intermediate. 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 .