Catalytic cycloaddition of CO2 to epoxides by the synergistic effect of acidity and alkalinity in a functionalized biochar

Ruthenium-based metal–organic framework catalyst for CO2 fixation onto epoxides

“…In these cases, nucleophilic attack is favored due to the increased electrophilicity of the least hindered carbon. 1,4 This is evident as each of these epoxides consistently incurs a 100% pressure drop in CO 2 after 24 hours at a 3 : 1 ratio, indicating that Ru-HKUST-1 is a highly active catalyst in stabilizing the alkoxide intermediate for CO 2 fixation (step II) at mild temperatures. 11 Furthermore, CO 2 has high solubility with epoxides such as SO and ECH in the liquid phase, where CO 2 gas molecules may freely interact and become more accessible to the substrate and catalyst.…”

“…PO is commonly used in this reaction because PC is an excellent example of a value-added product owing to its commercial use as a green alternative for organic solvents. 1,4 Catalytic reaction optimization revealed that at 50 °C, we achieved high conversions (>90%). At this temperature, it was found that Ru-HKUST-1 could catalyze the reaction most effectively at 7 bar (93%), but was also able to give a modest conversion of 56% at 1 bar.…”

“…While the rate of PC formation benefits greatly from higher epoxide concentration and catalyst specificity, it is important to note that the reaction strongly depends on the substrate type. 1,4…”

“…1 Nonetheless, Ru-HKUST shows a higher conversion than other catalysts reported in the literature. 3,4 Terminal epoxides with strong electron-withdrawing groups, such as styrene oxide (SO), epichloroyhydrin (ECH) and glycidol (GLY), are predicted to have faster reaction rates. In these cases, nucleophilic attack is favored due to the increased electrophilicity of the least hindered carbon.…”

Chemoselective and diastereodivergent synthesis of new spirooxindolo-pyrrolizidines and pyrrolidines stemming from unsymmetrical 1,3-bis(arylidene)tetral-2-ones: a combined experimental and theoretical study

“…In this context, the cycloaddition reaction is conceptually the most adopted synthesis approach to reach heterocyclic compounds. [1][2][3] This basic reaction despite being known for quite a while still solicits the attention of many researchers, 4,5 since it occurs most often with sufficiently high yields 6,7 and proceeds with an interesting diastereo-and enantio-selectivity 8,9 to provide access to a wide range of hybrid products that are hard to reach by other synthetic routes. Several variants of this reaction have emerged, and in the few last years, a new concept has been developed: the one-pot cycloaddition reaction 10 which turns it into a real synthetic masterpiece compared to domino reactions because it allows a significant reduction of the required time as well as skips all intermediate steps of purification.…”