Upgrading Carbon Dioxide by Incorporation into Heterocycles

Abstract

Carbon dioxide is commonly regarded as the primary greenhouse gas, but from a synthetic standpoint can be utilized as an alternative and sustainable C1 synthon in organic synthesis rather than a waste. This results in the production of organic carbonates, carboxylic acids, and derivatives. Recently, CO2 has emerged as an appealing tool for heterocycle synthesis under mild conditions without using stoichiometric amounts of organometallic reducing reagents. This Minireview summarizes recent advances on methodologies for CO2 incorporation into N-, O-, and C-nucleophiles to provide various heterocycles, including cyclic carbamates, benzoxazine-2-one, 4-hydroxyquinolin-2-one, quinazoline-2,4(1 H,3 H)-diones, benzimidazolones, α-alkylidene cyclic carbonate.

Sustainable conversion of carbon dioxide: the advent of organocatalysis

“…Heterocyclic structures that incorporate a "carbonate" or "carbamate" fragment as highlighted in Scheme 8, can serve as valuable monomers of polyurethanes and polycarbonates, drugs, electrolytes or reagents in a wide range of chemical transformations, [108][109][110][111][112] and therefore have attracted a great deal of interest in industrial and academic research. The most elegant way of producing these heterocyclic scaffolds involves coupling reactions of CO 2 with readily available epoxides or aziridines in the presence of a suitable catalyst.…”

Delineation of the Critical Parameters of Salt Catalysts in the N‐Formylation of Amines with CO2

“…[1] However,i ts inherent high stability limits its uncatalyzed reactions to high energy substrates. [12][13][14] Synthetic modification of the cation and/or anion allows an ear-infinite number of salts to be prepared, [15,16] whiles imultaneously allowing their performance to be tuned for ad esired application.H owever,t he design of more efficient salt catalysts is frequently hampered by limited mechanistic understanding and incomplete structure activity relationships, in part due to al ack of benchmark reactionc onditions. Ionic liquids( ILs) and other simples alts are promising catalysts for an umber of CO 2 related applications including the synthesis of cyclic carbonates, [2][3][4] quinazolinediones, [5,6] oxazolidinones, [7,8] N-methylamines, [9] N-formylamines [10,11] and other compounds.…”

CO2 Adducts of Carbodicarbenes: Robust and Versatile Organocatalysts for Chemical Transformation of Carbon Dioxide into Heterocyclic Compounds

“…To overcome this obstacle, employment of high‐energy starting materials seems to be wise choice for the use of inactive CO 2 as a reactant. Therefore, the atom‐economical reactions involving carboxylative cyclization of CO 2 with aziridines, epoxides, or propargylic alcohols/amines to afford five‐membered cyclic urethanes or carbonates have been intensively studied. A variety of catalysts have been developed, including alkali metal salts, transition‐metal complexes, ionic liquids, metal–organic frameworks, polymers, quaternary ammonium/phosphonium salts, small‐molecule organocatalysts, and so on.…”