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.
Direct organocatalytic aldol reactions in buffered aqueous media
作者:Armando Córdova、Wolfgang Notz、Carlos F. Barbas III
DOI:10.1039/b207664k
日期:——
Organocatalytic cross-aldol reactions catalyzed by cyclic secondary amines in aqueous media provide a direct route to a variety of aldols including carbohydrate derivatives and may warrant consideration as a prebiotic route to sugars.
Oxazoline-Substituted Prolinamide-Based Organocatalysts for the Direct Intermolecular Aldol Reaction between Cyclohexanone and Aromatic Aldehydes
作者:Simon Doherty、Julian G. Knight、Amy McRae、Ross W. Harrington、William Clegg
DOI:10.1002/ejoc.200700922
日期:2008.4
Oxazoline-substituted prolinamides catalyse the direct asymmetric aldol reaction between cyclohexanone and a range of aldehydes to give excellent conversions and enantioselectivities up to 84 % under optimum conditions. Reactions were highly substrate-specific with electron-deficient aldehydes giving the highest yields and ee values. The absolute configuration of the 4-chlorobenzaldehyde-derived product
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