Synthesis and Characterization of Monosaccharide Derivatives and Application of Sugar-Based Prolinamides in Asymmetric Synthesis
作者:Jyoti Agarwal、Rama Krishna Peddinti
DOI:10.1002/ejoc.201200522
日期:2012.11
were converted into the corresponding prolinamide organocatalysts (i.e., 1a, 2a, 3a, and 3b) in high yields. The catalytic activity of these sugar-based prolinamide organocatalysts was demonstrated in asymmetric aldol reactions in various solvents and at different temperatures. The oraganocatalyst 3a was shown to be an efficient and powerful organocatalyst for the enantioselective aldol reaction of various
Design and preparation of a novel prolinamide-based organocatalyst for the solvent-free asymmetric aldol reaction
作者:Rafaela de S. Martins、Mathias P. Pereira、Pedro P. de Castro、Fernanda I. Bombonato
DOI:10.1016/j.tet.2019.130855
日期:2020.1
proline-derived catalyst, providing access to the desired adducts in up to 95% yield, 1:19 syn/anti and 98% e.e. Moreover, even sterically bulky aldehydes and substituted cyclohexanones were well tolerated. DFT calculations and control experiments indicated that several hydrogen bonding interactions between the aldehyde and the enamine intermediate are responsible for the stereoselective chiral induction process
benzenesulfonic acid (DBSA) leads to highly effective and selective organocatalysts in water. The in situ generated catalysts catalyze highly stereoselective desymmetrization of prochiral ketones via directaldol reactions (up to >16:1 dr, >99% ee) in water using micelle as reaction media. The current strategy was also applied in asymmetric Michael addition leading to a catalytic system with good activity
Highly Enantio- and Diastereoselective Organocatalytic Desymmetrization of Prochiral Cyclohexanones by Simple Direct Aldol Reaction Catalyzed by Proline
Panacea for aldoldesymmetrizations: We describe an easy entry for the desymmetrization of 4‐substituted‐cyclohexanonescatalyzed by proline, using as cocatalysts different hydrogen‐bonding donors (see scheme), which dramatically improves the catalytic efficiency of proline in desymmetrizationreactions.
Presented herein is a redox tuning strategy for asymmetric aminocatalysis with a designed chiral ferrocenophane. Under redox control, the ferrocenophane catalyst efficiently catalyzes the asymmetric aldol reaction at room temperature with excellent yield and good stereoselectivity. Moreover, the redox‐active ferrocene moiety also served as phase‐tag to facilitate catalyst recovery and reuse. The catalyst