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A selective procedure for the synthesis of 5-substituted N-aryloxazolidinones by the coupling of epoxides with arylcarbamates catalyzed by ionic liquids has been developed. The effects of reaction time, reactant molar ratio, amount of catalyst, and temperature were investigated. Under the optimal reaction conditions, BmimOAc exhibited efficient catalytic activity compared with other ionic liquids leading to the formation of 5-substituted N-aryloxazolidinones in excellent yields. In addition, chiral 5-substituted oxazolidinones were synthesized by this procedure in good-to-excellent yields with enantiomeric excesses in excess of 99.9 % starting from chiral terminal epoxides. A possible reaction mechanism is discussed in accord with the results obtained by 1H NMR spectroscopy and DFT calculations, which indicate the cooperative activation by BmimOAc through the formation of hydrogen bonds with the substrates. [ABSTRACT FROM AUTHOR]

[Display omitted] Ionic liquids/organic bases synergistically catalyze the cycloaddition of CO 2 and epoxides under atmospheric pressure with high activity. • Ionic liquids/organic bases intermolecular synergistic catalytic system was developed for CO 2 cycloaddition under atmospheric pressure. • The synergistic effect presumably ascribes to the activation of epoxides by ionic liquids and CO 2 by organic bases. • Secondary amines activate CO 2 to form carbamic acids, and tertiary amines activate CO 2 to form bicarbonate salts with the aid of water. • Plausible synergistic catalyzed mechanisms are proposed based on the NMR, FT-IR investigations and DFT calculations. An intermolecular synergistic catalytic system consisting of ionic liquids and organic bases is developed for the cycloaddition of CO 2 and epoxides. This strategy realizes the cycloaddition takes place under atmospheric pressure of CO 2 with high activity. NMR, FT-IR spectroscopy and DFT calculations are applied to investigate the synergistic effect and reaction mechanism on molecules. Plausible ionic liquids/secondary amines and ionic liquids/tertiary amines catalyzed mechanisms are proposed and further confirmed by more detailed DFT calculations including reaction pathways and energy profiles, respectively. The procedure reported here represents a facile, cost-effective and energy-efficient route for chemical fixation of CO 2 into 5-membered cyclic carbonates. [ABSTRACT FROM AUTHOR]

Chemical equations are presented for the article "Selective Synthesis of 5-Substituted N-Aryloxazolidinones by Cycloaddition Reaction of Epoxides with Arylcarbamates Catalyzed by the Ionic Liquid BmimOAc" by B. Chen, published in the periodical "European Journal of Organic Chemistry."