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

Abstract

Chemical valorization of CO2 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, CO2, and 2‐aminoethanols was developed for the synthesis of 2‐oxazolidinones and an equal amount of α‐hydroxyl ketones promoted by Ag2O/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/CO2 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 CO2.

Recent Advances in the Chemical Fixation of Carbon Dioxide: A Green Route to Carbonylated Heterocycle Synthesis

“…In all the papers, yields of oxazolidinones and ketones by-product are comparable. Authors performed control experiments, DFT calculation, kinetic and NMR studies and from these data suggested the reaction pathway depicted in Scheme 22 [177], which was confirmed in the other papers. The first proposed catalyst was the couple Ag 2 O and tetramethylguanidine (Scheme 22) [177].…”

“…Authors performed control experiments, DFT calculation, kinetic and NMR studies and from these data suggested the reaction pathway depicted in Scheme 22 [177], which was confirmed in the other papers. The first proposed catalyst was the couple Ag 2 O and tetramethylguanidine (Scheme 22) [177]. The reaction was also applied to diols; 1-phenylethan-1,2-diol and 3-phenoxypropan-1,2-diol gave the corresponding cyclic carbonates in 95% and 58%, respectively.…”

“…To shift the equilibrium to 2-oxazolidinones dehydrating agents or auxiliaries are often needed, with generation of waste. Among dehydrating agents in the last two years, He and co-workers proposed propargyl alcohols and published some papers with different catalysts to carry out this reaction [177][178][179].…”

Incorporation of CO2 into carbonates through carboxylation/hydration reaction

“…165,166 The Ag 2 O/1,1,3,3-tetramethylguanidine (TMG) catalytic system was also demonstrated to be an effective catalytic method by He's group in a three-component reaction of terminal propargylic alcohols, CO 2 , and 1,2-diols for the formation of cyclic carbonates and α-hydroxyl ketones. 168 The addition of terminal propargyl alcohols overcame the thermodynamic limitations in the condensation reaction of 1,2-diols with CO 2 .…”

Ionic Liquid-Promoted Three-Component Domino Reaction of Propargyl Alcohols, Carbon Dioxide and 2-Aminoethanols: A Thermodynamically Favorable Synthesis of 2-Oxazolidinones

“…To shift the equilibrium to 2-oxazolidinones, harsh reaction conditions [43][44][45][46][47], dehydrating agents or auxiliaries are often needed [13,[48][49][50][51]; thus the generation of wasteful by-products is unavoidable. As an alternative strategy, our group introduced propargyl alcohols into the reaction system of amino alcohols and CO2 to circumvent this thermodynamic limitation [52][53][54]. As descripted in Scheme 1, this three-component cascade reaction is composed of carboxylative cyclization and the following intermolecular nucleophilic ring-opening and further intramolecular nucleophilic cyclization.…”