Selective Synthesis of 5-Substituted N-Aryloxazolidinones by Cycloaddition Reaction of Epoxides with Arylcarbamates Catalyzed by the Ionic Liquid BmimOAc

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 H-1 NMR spectroscopy and DFT calculations, which indicate the cooperative activation by BmimOAc through the formation of hydrogen bonds with the substrates.