依靠商业上可买到的催化剂构件的组装,已经实现了具有无与伦比的底物多样性的高度立体控制的季碳(所有碳取代的)形成。例如,三组分催化剂体系的原位组装允许将α-支链醛加成到硝基烯烃或马来酰亚胺亲电试剂中(Michael产品),而将α-支链醛加成可以得到曼尼希反应产物。观察到非常高的收率,在18个实例中,有15个实例的96-99%ee被观察到。使用外消旋的α-支链醛,可以通过高效的原位动态动力学拆分在高非对映异构体和对映体过量(八个实例)中形成两个连续的(四级-三级)立体中心,尤其是解决了已知的马来酰亚胺亲电试剂的缺点。该方法具有实用价值,仅需要1.2当量的醛,每种催化剂组分的负载量为5.0 mol%,例如O- t Bu- L-苏氨酸(O- t Bu- L- Thr),磺酰胺,DMAP或O-吨BU-大号-Thr,KOH,和室温下的反应。作为亮点,乙基异戊醛(7公开了添加),提供迄今已知的最拥挤的含
A highly efficient asymmetric Michael addition of α,α-disubstituted aldehydes to maleimides catalyzed by primary amine thiourea salt
作者:Feng Yu、Zhichao Jin、Huicai Huang、Tingting Ye、Xinmiao Liang、Jinxing Ye
DOI:10.1039/c0ob00154f
日期:——
The first highlyefficientMichaeladdition of challenging α,α-disubstituted aldehydes to maleimides catalyzed by a simple bifunctional primary amine thiourea catalyst/benzoic acid system has been successfully developed to generate quaternary carbon centers in high yields (up to 99%) with excellent enantioselectivities (91–99%).
An Asymmetric Michael Addition of α,α-Disubstituted Aldehydes to Maleimides Leading to a One-Pot Enantioselective Synthesis of Lactones Catalyzed by Amino Acids
作者:Christoforos G. Kokotos
DOI:10.1021/ol4008662
日期:2013.5.17
A cheap and fast construction of both enantiomers of substituted succinimides is reported. α- or β-amino acids, such as β-phenylalanine and α-tert-butyl aspartate, were found to be efficient organocatalysts for the reaction between α,α-disubstituted aldehydes and maleimides. Products containing contiguous quaternary-tertiary stereogenic centers are obtained in high to quantitative yields and excellent
Calixarene-based chiral primary amine thiourea promoted highly enantioselective asymmetric Michael reactions of α,α-disubstituted aldehydes with maleimides
作者:Mustafa Durmaz、Abdulkadir Sirit
DOI:10.1016/j.tetasy.2013.09.010
日期:2013.12
Calix[4]arene based chiral bifunctional thiourea-primary amines have been shown to act as effective catalysts for the Michael addition of aldehydes to maleimides for the first time. The corresponding adducts were generally obtained preferentially in (R)- or (S)-forms with high yields (up to 99%) and with high to excellent enantioselectivities (up to 98% ee). (C) 2013 Elsevier Ltd. All rights reserved.