Catalysis Letters, Vol.141, No.9, 1324-1331, 2011
Pyrrolidine-Based Chiral Quaternary Alkylammonium Ionic Liquids as Organocatalysts for Asymmetric Michael Additions
A series of chiral pyrrolidine-type quaternary alkylammonium ionic liquids were synthesized and served as efficient catalysts for asymmetric Michael additions of aldehydes and ketones to nitroolefins, and the corresponding adducts were obtained in excellent enantioselectivities (> 99% ee) and diastereoselectivities (> 99% dr) under solvent-free reaction conditions. Furthermore, the catalyst 7c could be recovered for next run of the reaction with similar yield and selectivity.