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 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.
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.