Asymmetric Michael reaction of aldehydes with β-nitroalkenes catalyzed by pyrrolidine-camphor derived organocatalysts bearing hydrogen-bond donors.Chirality. 2012 Apr; 24(4):271-5.C
Several pyrrolidine-camphor derived organocatalysts were designed and synthesized. These organocatalysts were used for direct Michael reaction of aldehydes with nitroalkenes to give the desired γ-nitrocarbonyl compounds in high yields (up to 99%), high diastereoselectivities (syn:anti up to 92:8), and good to excellent enantioselectivities (up to 94% ee). Possible transition-state model was also proposed for this asymmetric transformation, which may involve hydrogen-bond interactions between the nucleophilic enamine formed in situ and the nitroalkenes.