water-compatible proline catalysts (4–6) derived from calixarene bearing a hydrophobic nature have been synthesised. It was found that the compound 4 was a highly efficient organocatalyst for aldol reactions occurred in the water. Under optimised reaction conditions, high yields (up to 82%), good enantioselectivities (ee up to 81%) and high diastereoselectivities (dr up to 91:9) were obtained.
Prolinamides of Aminouracils, Organocatalyst Modifiable by Complementary Modules
作者:Karen M. Ruíz-Pérez、Beatriz Quiroz-García、Marcos Hernández-Rodríguez
DOI:10.1002/ejoc.201800886
日期:2018.11.8
Prolinamide organocatalysts with aminouracils have the features of enhanced NH acidity, an additional hydrogen‐bond donor and the self‐assembly with complementary modules by Watson–Crick pairing. Each module affects the selectivity of the reaction and particularly 2,6‐diaminopyridine is beneficial to the selectivity in the reaction.
successfully used as a cocatalyst for L-proline catalyzed aldolreactions in the presence of water. The anticonfigured products were obtained with good yields (up to 94%), high diastereoselectivities (up to 95:5), and high enantiomeric excesses (up to 93% ee ). The successful results for catalytic efficiency of L-proline in the presence of water reveal the importance of the hydrophobic nature of cholesterol
Simple peptides and their analogues having a primary amino group as the catalytic residue mediate the direct asymmetric intermolecular aldol reaction with high stereoselectivity and furnish the corresponding aldol products with up to 99% ee; this intrinsic ability of highly modular peptides may explain the initial molecular evolution of aldolase enzymes.
Proline dipeptides containing fluorine moieties as oganocatalysts for the asymmetric aldol reaction
作者:Ardiol Ahmetlli、Nikoleta Spiliopoulou、Angeliki Magi-Oikonomopoulou、Dimitrios-Triantaffylos Gerokonstantis、Panagiota Moutevelis-Minakakis、Christoforos G. Kokotos
DOI:10.1016/j.tet.2018.08.038
日期:2018.10
demonstrated, where aromaticaldehydes afforded products in high yields (up to 100%) with excellent diastereo- (up to 95:5) and enantioselectivities (up to 97%), whereas the aliphaticaldehydes afforded also excellent selectivities, but relatively low yield. A simple addition of fluorine to a dipeptide analogue affords organocatalysts with new interesting properties that can catalyze the aldol reaction