Enantioselective 1,3-Dipolar Cycloadditions of Unsaturated Aldehydes Promoted by A Poly(ethylene glycol)-Supported Organic Catalyst
作者:Alessandra Puglisi、Maurizio Benaglia、Mauro Cinquini、Franco Cozzi、Giuseppe Celentano
DOI:10.1002/ejoc.200300571
日期:2004.2
MacMillan’s catalyst by anchoring a tyrosine-derived imidazolidin-4-one by means of a spacer to the monomethyl ether of poly(ethylene glycol) (MW = 5000 Da). The supported organic catalyst was employed in some 1,3-dipolar cycloadditions involving α,β-unsaturated aldehydes and nitrones. The products were obtained in enantiomeric excesses very similar to those observed with the non-supported catalyst, but the
我们开发了一种聚合物负载型 MacMillan 催化剂,通过将酪氨酸衍生的 imidazolidin-4-one 锚定到聚乙二醇单甲醚 (MW = 5000 Da) 上。负载型有机催化剂用于一些涉及 α,β-不饱和醛和硝酮的 1,3-偶极环加成反应。以与使用非负载型催化剂观察到的那些非常相似的对映体过量获得产物,但化学产率稍低。利用聚合物载体的溶解度曲线,催化剂很容易与反应产物分离、回收和再循环。催化剂回收伴随着对映选择性的非常边缘的侵蚀(如果有的话)和化学效率的更显着降低。我们将后一种现象主要归因于催化剂在反应条件下的内在不稳定性,然而,这是非负载型和负载型催化剂的共同特征。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)