The first C2‐symmetric immobilized organocatalyst for asymmetric aldol reactions containing the (1R,2R)‐bis[(S)‐prolinamido]cyclohexane unit tagged with two imidazolium+/PF6– ion pairs has been synthesized. In its presence, (hetero)aromatic aldehydes reacted with linear or cyclic ketones in aqueous media to yield chiral aldols with high diastereo‐ and enantioselectivities and the catalyst could be recovered and reused at least 10 times without any decrease in the reaction rate or selectivity.
Novel C-symmetric N,N'-bis-[(pyrrolidin-2-yl)methyl-squaramide] TFA salts bearing (R,R)- or (S,S)-1,2-di(pyridin-2-yl)ethane spacer groups were synthesized and applied, in combination with TEA, as efficient organocatalysts for asymmetric reactions between cyclohexanone derivatives and β-nitrostyrenes to afford the corresponding Michael adducts in high yields with good to excellent enantioselectivity. The catalytic procedure is readily scalable and recyclable over four times without a negative impact on the selectivity of the reaction. Some of the prepared compounds are valuable precursors to useful bioactive molecules.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.