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
Protonated N'-benzyl-N'-l-prolyl-l-proline hydrazide has been developed as a highly enantioselective catalyst for the asymmetric directaldolreaction of aromatic aldehydes with ketones.
Unexpected Beneficial Effect of ortho-Substituents on the (S)-Proline-Catalyzed Asymmetric Aldol Reaction of Acetone with Aromatic Aldehydes
作者:Benjamin List、Alberto Martínez、Manuel van Gemmeren
DOI:10.1055/s-0033-1340920
日期:——
An intriguing effect of electronegative 2,6-substituents on the stereochemical outcome of (S) -proline-catalyzed aldol reactions between benzaldehyde derivatives and acetone is reported. Remarkably high enantioselectivities can be achieved with such substrates.
Thiazolidine-based organocatalysts for a highly enantioselective direct aldol reaction
作者:Raoní S. Rambo、Paulo H. Schneider
DOI:10.1016/j.tetasy.2010.07.028
日期:2010.9
exhibits the highest catalytic performance working in an aqueous medium. It catalyzed the directcatalyticasymmetric intermolecular aldolreaction between unmodifiedketones and an aldehyde with excellent stereocontrol and furnished the corresponding aldol products in up to 99% ee. Compound 3a also showed excellent asymmetriccatalytic activity in the asymmetric Michael reaction (up to 99% ee).
Inducing chirality on ZnS nanoparticles for asymmetric aldol condensation reactions
作者:Ekta Shah、Hemant P. Soni
DOI:10.1039/c3ra41285g
日期:——
aldol reaction of several aldehydes with acetone to achieve chiral β-hydroxycarbonyl compounds in good yields and enantioselectivity at room temperature. The peculiarity of our strategy is that the reaction is carried out at room temperature and does not involve any co-solvent for solubility purposes. The selectivity of the developed heterogeneous catalyst leads to only (R)-β-hydroxy carbonyl compounds