Unprecedented bifunctional enamine–metal Lewisacidcatalysts have been developed. In this bifunctional catalytic system, a tridentateligand tethered with a chiral secondary amine was designed to solve the acid–base self-quenching problem leading to catalyst inactivation. This new bifunctional enamine–metal Lewisacidcatalyst was found to catalyze aldol reactions of ketones efficiently in high yields
Asymmetric Aldol Reaction Catalyzed by the Anion of an Ionic Liquid
作者:Vincent Gauchot、Andreea R. Schmitzer
DOI:10.1021/jo300737u
日期:2012.6.1
its applications as a catalyst for the asymmetric aldolreaction. By performing the aldolreaction in [Bmim]NTf2 as a solvent, we report excellent isolated yields of the aldol product (up to 99%), as well as modest to excellent selectivities (dr superior to 99:1. ee up to 89%). Mechanistic insights and the origins of the selectivity of the aldolreaction are discussed on the basis of the results obtained
SULFONAMIDE-BASED ORGANOCATALYSTS AND METHOD FOR THEIR USE
申请人:Carter Rich Garrett
公开号:US20100184986A1
公开(公告)日:2010-07-22
Organocatalysts, particularly proline sulfonamide organocatalysts, having a first general formula as follows are disclosed.
Embodiments of a method for using these organocatalysts also are disclosed. The method comprises providing a disclosed organocatalyst, and performing a reaction, often an enantioselective or diastereoselective reaction, using the organocatalyst. Solely by way of example, disclosed catalysts can be used to perform aldol reactions, conjugate additions, Michael additions, Robinson annulations, Mannich reactions, α-aminooxylations, α-hydroxyaminations, α-aminations and alkylation reactions. Certain of such reactions are intramolecular cyclizations used to form cyclic compounds, such as 5- or 6-membered rings, having one or more chiral centers. Disclosed organocatalysts generally are much more soluble in typical solvents used for organic synthesis than are known compounds. Moreover, the reaction yield is generally quite good with disclosed compounds, as is their enantioselective and diastereoselective effectiveness.
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
Primary amine-metal Lewis acid bifunctional catalysts: the application to asymmetric direct aldol reactions
作者:Zhenghu Xu、Philias Daka、Hong Wang
DOI:10.1039/b912728c
日期:——
The first example of metal Lewis acid-primary amine bifunctional cooperative catalyst derived from primary amino acids was developed, and it was found to catalyze aldolreactions of cyclic ketones highly efficiently with very good to excellent stereoselectivities.