Enantiomers of (2R∗,3R∗)-1-methyl-5-oxo-2-phenyltetrahydro-1H-pyrrolidine-3-carboxylic acid as novel chiral resolving agents
作者:Katarzyna Piwowarczyk、Anna Zawadzka、Piotr Roszkowski、Joanna Szawkało、Andrzej Leniewski、Jan K. Maurin、Darius Kranz、Zbigniew Czarnocki
DOI:10.1016/j.tetasy.2008.01.014
日期:2008.2
A series of (2R*,3R*)-1-methyl-5-oxo-2-aryltetrahydro-1H-pyrrolidine-3-carboxylic acids were prepared and their structures were proven with X-ray crystallography. Racemic acid 5 has been resolved into enantiomers (2S,3S)-5 and (2R,3R)-5 by the formation of diastereomeric salts with brucine 9 and strychnidine 10, respectively. The ability of these enantiomers to serve as chiral discriminating agents was demonstrated by the chromatographic separation of diastereomeric amides and esters. Also, some preliminary results on the enantioselective reduction of prochiral imines with sodium borohydride modified by (2R,3R)-5 were collected. (C) 2008 Elsevier Ltd. All rights reserved.
Dynamic Asymmetric Multicomponent Resolution: Lipase-Mediated Amidation of a Double Dynamic Covalent System
作者:Pornrapee Vongvilai、Olof Ramström
DOI:10.1021/ja9052015
日期:2009.10.14
The Strecker reaction is one of the most important multicomponentreactions developed, leading to alpha-aminonitriles that are versatilesubstrates for many synthetic applications. In the present study, this reaction type has been applied to a double dynamic covalent resolution protocol, leading to efficient C-C- and C-N-bond generation as well as chiral discrimination. The combination of transimination
Strecker 反应是已开发的最重要的多组分反应之一,导致 α-氨基腈成为许多合成应用的通用底物。在本研究中,这种反应类型已应用于双动态共价拆分协议,导致有效的 CC 和 CN 键生成以及手性区分。转亚胺化与亚胺氰化的结合使得围绕单个受限制结构的立体中心在多个方向上进行动态交换。这种多重交换过程可以在很短的时间内从少量的起始材料中产生范围广泛的化合物。在热力学控制下产生的双动态共价系统,随后在一锅法中与动力学控制的脂肪酶介导的转酰基作用偶联。这导致动态系统的完全分辨率,产生酶的最佳 N-酰基-α-氨基腈,其中单独的化学酶促反应可以以良好的产率产生对映异构纯的酰化 N-取代 α-氨基腈。