[4?(2?Hydroxyphenyl)imidazolium Salts as Organocatalysts for Cycloaddition of Isocyanates and Epoxides to Yield Oxazolidin?2?ones

Novel salts based on 1,3-dibutyl-4-(2-hydroxyphenyl)-1H-imidazolium bromide or iodide have been developed as bifunctional organocatalysts for the cycloaddition reaction of epoxides and isocyanates to form 3,4- 3,5-disubstituted oxazolidin-2-ones. The molecular structure these compounds was determined spectroscopically confirmed by X-ray diffraction analysis. Imidazolium were screened catalysts produce a range oxazolidinones. influence substituents aromatic ring counterion catalytic activity studied, showing that 1,3-dibutyl-4-(5-fluro-2-hydroxyphenyl)-1H-imidazolium (4 d) most active catalyst this process in absence cocatalyst.