A polystyrene-supported 9-amino(9-deoxy)epi quinine derivative for continuous flow asymmetric Michael reactions
作者:Javier Izquierdo、Carles Ayats、Andrea H. Henseler、Miquel A. Pericàs
DOI:10.1039/c5ob00325c
日期:——
derivative catalyzes Michael reactions affording excellent levels of conversion and enantioselectivity using different nucleophiles and structurally diverse enones. The highly recyclable, immobilized catalyst has been used to implement a single-pass, continuous flow process (residence time: 40 min) that can be operated for 21 hours without significant decrease in conversion and with improved enantioselectivity
An Adverse Effect of Higher Catalyst Loading and Longer Reaction Time on Enantioselectivity in an Organocatalytic Multicomponent Reaction
作者:Tushar M. Khopade、Trimbak B. Mete、Jyotsna S. Arora、Ramakrishna G. Bhat
DOI:10.1002/chem.201800278
日期:2018.4.20
An enantioselective organocatalytic multicomponent reaction of aldehydes, ketones, and Meldrum's acid has been developed. A cinchona‐based primary amine (1 mol %) catalyses the multicomponent reaction via the formation of the Knoevenagel product and a chiral enamine to form enantiopure δ‐keto Meldrum's acids in a tandem catalytic pathway. An adverse effect of higher catalyst loading and longer reaction