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
6-aryl-2,6-hexanediones was achieved with chiral secondary amine catalyzed intramolecular aldolization. The current kinetic resolution protocol enables the synthesis of bothenantiomers of cyclohexenones with moderate to good enantioselectivity.
Direct asymmetric vinylogous Michael addition of 3-alkylidene oxindoles to chalcones catalyzed by a chiral N,N′-dioxide ytterbium(<scp>iii</scp>) complex
A chiral ytterbium(III)-N,N'-dioxide catalyst system has been developed for the catalytic direct asymmetric vinylogous Michaeladdition of 3-alkylidene oxindoles to chalcones, delivering the gamma-substituted alkylideneoxindoles in high yields, enantioselectivities and good Z/E selectivities under mild reaction conditions.
Organocatalytic enantioselective decarboxylative Michael addition of β-ketoacids to α,β-unsaturated ketones
作者:Young Ku Kang、Hyun Joo Lee、Hyoung Wook Moon、Dae Young Kim
DOI:10.1039/c2ra21945j
日期:——
EnantioselectivedecarboxylativeMichaeladdition reactions promoted by chiral primary amine organocatalysts have been developed, allowing the facile synthesis of the corresponding chiral 1,5-diketones with excellent enantioselectivity (up to 97% ee). The method reported represents a valuable approach of utilizing β-ketoacids as synthetic equivalents of aryl methyl ketones.
Direct asymmetric Michael addition of ketones to chalcones catalyzed by a hydroxyphthalimide derived triazole–pyrrolidine
作者:Togapur Pavan Kumar、Mohammad Abdul Sattar、Vanka Uma Maheshwara Sarma
DOI:10.1016/j.tetasy.2013.11.002
日期:2013.12
An efficient protocol for the enantioselective Michael additions of ketones to chalcones catalyzed by a hydroxyphthalimide linked triazole-pyrrolidine derivative has been developed. The corresponding products, 1,5-dicarbonyl compounds, were obtained in good yields with high levels of stereoselectivities under mild reaction conditions employing benzoic acid as an additive. (C) 2013 Elsevier Ltd. All rights reserved.