描述了作为活化氨基酸衍生物的氮杂内酯的第一次催化不对称共轭加成反应向烯酮的发展和进一步发展。第一代方法是从孤立的氮杂内酯开始的,而第二代方法中的氮杂内酯可以从外消旋的N开始原位生成。苯甲酰化氨基酸。第三个进化阶段可以利用外消旋未保护的α-氨基酸直接形成高度对映体富集和非对映体纯的带掩蔽季铵氨基酸产物,并带有一个附加的叔立体中心。通过使用稳固的平面手性bis-Pd催化剂,布朗斯台德酸(HOAc或BzOH; Ac =乙酰基,Bz =苯甲酰基)和布朗斯台德碱(NaOAc),通过协同活化来实现逐步经济转型。特别是第二代和第三代方法提供了快速而多样化的途径,可从廉价的散装化学品中获得生物学上令人感兴趣的非天然季氨基酸衍生物。这样,可以以非对映体纯形式制备高度对映体富集的无环α-氨基酸,α-烷基脯氨酸和α-烷基焦谷氨酸衍生物。此外,
[8+2] Formal Cycloaddition Reactions of Tropones with Azlactones under Brønsted Acid Catalysis and Synthesis of α-(2-Tropyl), α-Alkyl α-Amino Acids
作者:Francisco Esteban、Ricardo Alfaro、Francisco Yuste、Alejandro Parra、José Luis García Ruano、José Alemán
DOI:10.1002/ejoc.201301774
日期:2014.3
The reaction of tropones with azlactones catalyzed by Bronsted acids affords a variety of dihydro-2H-cyclohepta[b]furan derivatives, corresponding to a formal [8+2] cycloaddition process. They can easily be opened by nucleophiles to afford a new type of α,α-disubstituted α-amino acid (or peptide) containing seven-membered rings at the quaternary position.
Asymmetric Aza-Diels–Alder Reactions of in Situ Generated β,β-Disubstituted α,β-Unsaturated N–H Ketimines Catalyzed by Chiral Phosphoric Acids
作者:Shunlong He、Huanchao Gu、Yu-Peng He、Xiaoyu Yang
DOI:10.1021/acs.orglett.0c01994
日期:2020.7.17
A novel asymmetricsynthesis of dihydropyridinones with vicinal quaternary stereocenters has been realized by asymmetric aza-Diels–Alder reactions of 3-amido allylic alcohols with oxazolones enabled by chiral phosphoric acid catalysis. A series of aryl/alkyl- and alkyl/alkyl-disubstituted 3-amido allylic tertiary alcohols and 4-substituted oxazolones could be well tolerated in these reactions, producing
Catalytic Asymmetric [2+3] Cyclizations of Azlactones with Azonaphthalenes
作者:Chun Ma、Jia‐Yu Zhou、Yi‐Zhu Zhang、Guang‐Jian Mei、Feng Shi
DOI:10.1002/anie.201801349
日期:2018.5.4
The first catalyticasymmetric [2+3] cyclization of azlactones with azonaphthalenes has been established. This strategy allowed the synthesis of a variety of chiral isatin derivatives in generally good yields and excellent enantioselectivities (up to 99 % yield, 98 % ee). The developed reaction has not only established a catalytic enantioselective [2+3] cyclization using azlactones as two‐carbon building
DBU-Promoted Formal [4+2] Annulation Reactions of o-Chloromethyl Anilines with Azlactones
作者:Jianfeng Xu、Haojie Ji、Chonglong He、Hongjie Gao、Weijun Fu
DOI:10.1055/s-0040-1706549
日期:2021.4
An efficient 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-mediated formal [4+2] annulation reaction of aza-ortho-quinone methides (aza-oQMs) (generated from o-chloromethyl anilines) with enolates (formed from azlactones) is disclosed, delivering biologically significant 3,4-dihydroquinolin-2(1H)-one derivatives in moderate to good yields. The salient features of this reaction include readily accessible
Enantioselective polyclonal antibodies have been produced and characterized to develop a high-throughput screening method for lipase activity fingerprinting, with a view to the enantioselective hydrolysis of azlactones.