Categories: Synthesis of O-Heterocycles >
Synthesis of dioxolanones
Treatment of aldehydes with sulfur ylides, followed by a reaction with CO2 under mild conditions, produces cyclic carbonates in preparative yields. Sodium iodide, which is formed in situ, promotes the reaction between the intermediate epoxides with CO2 at ambient conditions, thus constituting a versatile metal-free synthesis of organic cyclic carbonates from aldehydes.
R. D. Aher, B. S. Kumar, A. Sudalai, Synlett, 2014, 25, 97-101.
In cycloadditions of carbon dioxide into epoxides to afford cyclic carbonates, a strained ion pair tris(alkylamino)cyclopropenium halide catalyst, in which the halide is repelled, is a very electrophilic H-bond donor, allowing it to activate the oxygen of the epoxide, while the more nucleophilic halide is better able to attack the methylene carbon of the epoxide.
J. Xu, A. Xian, Z. Li, J. Liu, Z. Zhang, R. Yan, L. Gao, B. Liu, L. Zhao, K. Guo, J. Org. Chem., 2021, 86, 3422-3432.
A H8-binaphthyl-linked hemisquaramide catalyst accelerated the synthesis of cyclic carbonates from epoxides and CO2 under mild and solvent-free conditions. Kinetic resolution was also achieved at −20°C (s = 3.0).
K. Takaishi, T. Okuyama, S. Kadosaki, M. Uchiyama, T. Ema, Org. Lett., 2019, 21, 1397-1401.
Coupling reactions of epoxides with carbon dioxide that proceed at atmospheric pressure at temperatures of less than 100°C are challenging. Tetraarylphosphonium salts (TAPS) catalyze the formation of five-membered cyclic carbonates by chemical fixation using 1 atm of carbon dioxide at 60°C. Electron-donating groups enhanced the reactivity of the used TAPS.
Y. Toda, Y. Komiyama, H. Esaki, K. Fukushima, H. Suga, J. Org. Chem., 2019, 84, 15578-15589.
Complexes of phosphonium ylides and metal halide salts efficiently catalyze the reaction of epoxides with carbon dioxide under mild conditions to provide five-membered cyclic carbonates, including disubstituted cyclic carbonates in good yields. Terminal epoxides could also be converted to N-aryl oxazolidinones with isocyanates using a similar catalytic system.
Y. Toda, K. Hashimoto, Y. Mori, H. Suga, J. Org. Chem., 2020, 85, 10980-10987.
In a simple and convenient method, NHC/ZnBr2 catalyzes the coupling of CO2 with epoxides. This catalytic system exhibits excellent activity and selectivity in the cycloaddition reactions of CO2 to terminal epoxides. The reaction can even be carried out under partial CO2 pressure and gives carbonates in high yields.
X. Liu, C. Cao, Y. Li, P. Guan, L. Yang, Y. Shi, Synlett, 2012, 23, 1343-1348.
A series of charge-containing thiourea salts catalyze cycloadditions of epoxides with CO2 under mild conditions to provide cyclic five-membered ring organic carbonates of broad interest from a synthetic, environmental, and green chemistry perspective.
Y. Fang, M. Tiffner, J. Schörgenhumer, R. Robiette, M. Waser, S. R. Kass, J. Org. Chem., 2018, 83, 9991-10000.
Acyclic guanidinium salts catalyze the formation of five-membered cyclic carbonates in good yields through cycloaddition of CO2 to epoxides at nearly ambient temperatures and pressures. To achieve good catalytic activity of the guanidinium salt, it is essential to have active hydrogens on the cation moiety as well as an iodide ion as the anion moiety.
N. Aoyagi, Y. Furusho, T. Endo, Synthesis, 2020, 52, 150-158.
A reaction of diphenyl carbonate and various diols provides highly valuable cyclic carbonates in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as organocatalyst. This practical, safe, and highly efficient carbonylation system successfully replaced highly toxic and unstable phosgene or its derivatives while maintaining the desired high reactivity. Moreover, this new system can be used to synthesize sterically demanding cyclic carbonates.
E. R. Baral, J. H. Lee, J. G. Kim, J. Org. Chem., 2018, 83, 11768-11776.
An efficient, versatile and practical gram-scale preparation of oxazolidinone, imidazolidinone and dioxolanone is achieved.
N. Alouane, A. Boutier, C. Baron, E. Vrancken, P. Mangeney, Synthesis, 2006, 860-864.
Sequential treatment of a 1,2-disubstituted olefin with m-CPBA, Br3CCO2H, and DBU results in the one-pot, stereospecific conversion of the olefin to the corresponding disubstituted cyclic carbonate. When a solution of a secondary allylic or homoallylic amine and Br3CCO2H is sequentially treated with m-CPBA then DBU, the product of the reaction is a cyclic carbamate.
S. G. Davies, A. M. Fletcher, W. Kurosawa, J. A. Lee, G. Poce, P. M. Roberts, J. E. Thomson, D. M. Williamson, J. Org. Chem., 2010, 75, 7745-7756.
A series of tetrahaloindate(III)-based ionic liquids (ILs) have been produced by microwave-assisted synthesis. These ionic liquids have been examined as catalyst in the reaction of CO2 with various epoxides to give cyclic carbonates. Tetrahaloindate(III)-based ILs are found to exhibit high catalytic activities. The effects of a variety of parameters (temperature, pressure, molar ratio of propylene oxide to catalyst), the mechanism, and the significant role of H-bonding interactions in the coupling reactions are discussed.
Y. J. Kim, R. S. Varma, J. Org. Chem., 2005, 70, 7882-7891.
The reaction of chiral 1-aminoalkylepoxides with CO2, generated from acidic treatment of an aqueous solution of NaHCO3 at room temperature, efficiently afforded enantiopure cyclic carbonates with total selectivity. Carbonates were readily transformed into the corresponding diols by reaction with LiAlH4 or by basic hydrolysis.
J. M. Concellón, V. del Solar, S. Carcía-Granda, M. R. Díaz, J. Org. Chem., 2007, 72, 7567-7568.