Chiral Ionic Liquids Derived from (-)-Ephedrine and Carbohydrates: Synthesis, Properties and Applications to Asymmetric Synthesis and Catalysis

摘要

A novel class of chiral ammonium and imidazolium-based ionic liquids containing a chiral moiety and a free hydroxyl function has been designed and synthesized using (-)-ephedrine, isosorbide and isosmannide as naturally chiral sources. Some physical properties of these salts such as melting point, glass-transition temperature, thermal degradation, chemical stability and specific rotation have been characterized. These chiral ionic liquids were found to catalyze the asymmetric Baylis-Hillman reaction, aza Diets-Alder reaction and Michael addition giving good yields and moderate stereoselectivities. Chiral ionic liquids are recycled while their efficiency is preserved.