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- and 3,5-disubstituted oxazolidin-2-ones. The molecular structure of these compounds was determined spectroscopically and confirmed by X-ray diffraction analysis. Imidazolium compounds were screened as catalysts to produce a range of oxazolidinones. The influence of the substituents on the aromatic ring and the counterion of the catalysts on the catalytic activity have been studied, showing that 1,3-dibutyl-4-(5-fluro-2-hydroxyphenyl)-1H-imidazolium iodide (4 d) was the most active catalyst for this process in the absence of a cocatalyst.
Bibliographical noteFunding Information:
. We gratefully acknowledge the financial support from the Ministerio de Economía y Competitividad (MINECO), Spain (grant nos. CTQ2017‐84131‐R, CTQ2016‐81797‐REDC and RED2018‐102387‐T Programa Redes Consolider)
We gratefully acknowledge the financial support from the Ministerio de Econom?a y Competitividad (MINECO), Spain (grant nos. CTQ2017-84131-R, CTQ2016-81797-REDC and RED2018-102387-T Programa Redes Consolider).
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- Imidazolium salts