Enantioselective Copper(I/II)-Catalyzed Conjugate Addition of Nitro Esters to β,γ-Unsaturated α-Ketoesters
作者:Sheng Zhang、Kun Xu、Fengfeng Guo、Yanbin Hu、Zhenggen Zha、Zhiyong Wang
DOI:10.1002/chem.201303512
日期:2014.1.20
A highly enantioselective Michael addition of nitroacetates to β,γ‐unsaturatedα‐ketoesters was developed by using chiral copper catalysts. The Michael addition products can be obtained in high yields with up to 99 % ee. With these densely functionalized products, the chiral cyclic nitrones, which are important synthetic intermediates, can be obtained in one step.
Organocatalytic Asymmetric Conjugate Addition and Cascade Acyl Transfer Reaction of α-Nitroketones
作者:Rui-jiong Lu、Yun-yun Yan、Jin-jia Wang、Quan-sheng Du、Shao-zhen Nie、Ming Yan
DOI:10.1021/jo2009752
日期:2011.8.5
Organocatalytic asymmetric conjugate addition of α-nitroketones to β,γ-unsaturated α-keto esters has been developed. A pyrrolidine-based thiourea–tertiary amine was identified as the best catalyst. The reaction was found to proceed via cascade conjugate addition and acyl transfer reaction. A number of α-nitroketones and β,γ-unsaturated α-keto esters were examined in this transformation. 5-Nitro-2-
Organocatalytic Activation of Pyruvates Toward Michael Addition to Nitroalkenes: Synthesis of γ‐Aminobutyric Acid (GABA) Derivatives
作者:Łukasz Adam Włoszczak、Romuald Karczewski、Jacek Mlynarski
DOI:10.1002/adsc.202301502
日期:2024.4.9
pyrrolidine-based catalyst can mimick enamine mechanism used by this enzyme to activate pyruvates in the asymmetricaddition to structurally diverse nitroalkenes to produce highly enantioenriched Michael adducts without the limitations in substrate structures associated with biocatalysts. In addition to confirming that optically pure pyrrolidines can serve as ultimately small organic catalysts in pyruvate
尽管丙酮酸在生物转化中发挥着重要作用,但丙酮酸盐在催化不对称合成领域的利用却出人意料地受到限制。这一说法也适用于烯胺催化,其中丙酮酸盐似乎是具有挑战性的底物。最近,文献中首次报道了丙酮酸在 NahE 酶的催化下,利用烯胺机制不对称加成到 β-硝基苯乙烯上的情况。现在,我们证明基于吡咯烷的催化剂可以模仿该酶使用的烯胺机制,在结构多样的硝基烯烃的不对称加成中激活丙酮酸,产生高度对映体富集的迈克尔加合物,而不受与生物催化剂相关的底物结构的限制。除了证实光学纯吡咯烷可以作为丙酮酸活化中的最终小型有机催化剂之外,我们还提出了一种极其简单且通用的合成光学纯γ-硝基酸的方法,γ-硝基酸是众所周知的活性药物成分(即 GABA)的前体衍生品
Organocatalytic conjugate addition of α-nitroacetates to β,γ-unsaturated α-keto esters and subsequent decarboxylation: synthesis of optically active δ-nitro-α-keto esters
作者:Rui-jiong Lu、Wen-tao Wei、Jin-jia Wang、Shao-zhen Nie、Xue-jing Zhang、Ming Yan
DOI:10.1016/j.tet.2012.09.014
日期:2012.11
Organocatalytic asymmetric conjugate addition of tert-butyl nitroacetates to β,γ-unsaturated α-keto esters has been developed. The subsequent in situ hydrolysis–decarboxylation of the adducts provided 5-nitro-2-oxopentanoates. A pyrrolidine-based thiourea-tertiary amine was identified as the best catalyst. A number of γ-aryl, γ-alkyl, and γ-heteroaryl β,γ-unsaturated α-keto esters and α-substituted