有机催化不对称Michael加成反应

有机催化的不对称合成反应是目前研究最为活跃的领域之一. 不对称Michael加成反应是合成众多重要的手性合成子和药物中间体的有效手段. 目前报道的催化Michael加成反应的有机催化剂主要有脯氨酸及其衍生物、手性咪唑啉酮、手性(硫)脲、金鸡纳碱衍生物等. 对各类有机催化剂在有机催化不对称Michael加成反应中的应用, 以及不对称诱导反应的机理、催化剂分子结构及反应条件对其催化活性和不对称诱导作用的影响进行了评述.     

双功能手性硫脲催化的不对称Michael加成反应研究进展

手性有机小分子催化是近年来不对称催化领域的一个热门研究课题.其具有反应条件温和、环境友好等优点,符合绿色化学的要求.手性氨基-硫脲类催化剂,特别是双功能的手性硫脲,已经在众多的不对称反应中表现出了优秀的催化性能.主要综述了双功能手性硫脲在不对称Michael加成反应中的应用,并对其前景及发展趋势作了展望.     

有机小分子不对称催化Michael加成的研究进展

有机小分子催化成为现在最热门的研究领域之一.不对称Michael加成反应是合成具有一个或多个手性中心合成砌块和药物中间体的重要方法.介绍了近3年来有机小分子伯胺衍生物、吡咯烷衍生物、(硫)脲、手性方酰胺和磷酸等在不对称催化Michael加成中的应用研究进展.对各种小分子结构和催化活性的关系、催化剂诱导活化机理以及各种催化体系在药物和关键中间体合成中的应用也进行详细的评述.     

手性磺酰胺有机小分子催化剂在不对称催化反应中的应用进展

有机小分子催化的不对称合成反应是目前研究最为活跃的领域之一.综述了磺酰胺类衍生物作为小分子催化剂在不对称反应(Michael加成反应、Mannich反应、羟醛缩合反应等)中的应用,讨论了磺酰胺中NH的酸性以及氢键性质在不对称催化反应中的的作用.     

手性氨基酸酰胺催化剂的发现及研究进展

自从L-脯胺酰胺被发现能高效催化不对称aldol反应以来,手性氨基酸酰胺催化剂的设计及不对称催化研究一直受到关注。特别是“烯胺-双氢键”模型的提出为设计新型有机小分子催化剂提供了理论依据,使催化剂的结构设计趋于多样化。本文重点总结了含有单氢键给体、双氢键给体及多氢键给体的氨基酸酰胺催化的不对称催化反应,主要包括不对称直接aldol反应、Mannich反应、Michael加成反应、环加成反应、串联环化反应、Biginelli反应等方面的研究进展。     

手性有机小分子催化的最新进展*

手性有机小分子催化是近年来不对称催化领域发展起来的一个研究热点。手性有机小分子催化具有反应条件温和,环境友好,催化剂易于回收利用等优点,符合绿色化学的要求。本文根据手性有机催化剂活化模式的不同,从烯胺催化、亚胺催化、氢键活化、卡宾催化、相转移催化以及光化学等方面对近年来的有机小分子催化的进展,特别是中国学者的工作做一简要评述。重点通过对不同催化体系下催化剂和反应底物之间立体效应和电子效应的考察,发现控制反应立体选择性以及活化惰性底物的规律,进而设计更加高效的手性有机小分子催化剂,完善和拓展有机小分子催化的不对称合成。     

脯氨酸衍生物催化手性Michael加成的研究进展

Michael加成是有机合成中形成C-C键的重要反应.近年来,对于不对称催化Michael加成反应的研究成为手性催化研究领域的热点之一.不含贵金属的有机小分子催化剂由于其温和、廉价、对环境友好等优点,其应用已成为催化领域的重要发展趋势.本文综述了脯氨酸衍生物催化手性Michael加成反应的研究进展,并对其发展前景作了展望.     

一种新型双亲性有机小分子催化剂在水相体系中催化环己酮与硝基烯烃直接不对称Michael加成反应

设计合成了一系列基于脯氨酸巯基咪唑衍生物的新型双亲性有机小分子催化剂,在水相中加入酸作为助催化剂,可以高效高选择性的催化环己酮与硝基烯烃的不对称Michael加成反应,非对映选择性和对映选择性分别高达99：1和96%.     

手性(硫)脲衍生物在不对称有机催化反应中的应用

手性(硫)脲衍生物是各种亲核试剂对亚胺、醛、缺电子烯烃加成反应的非常有效的有机催化剂之一, 已成功应用于对映选择性催化Strecker反应、Michael加成反应、Mannich反应、Baylis-Hillman反应、Henry反应等一系列重要的有机合成反应. 手性(硫)脲衍生物具有催化活性高、对映选择性和功能基相容性好、易于制备和修饰、适用范围广等优点, 成为近年来研究较多的不对称反应有机催化剂. 对手性(硫)脲衍生物在有机催化不对称合成中的应用研究进展进行了评述.     

蒽酮与β-硝基苯乙烯的不对称Michael加成反应

不对称催化Michael加成反应是一类重要的形成碳—碳键的反应,以蒽酮作为亲核试剂的不对称Michael反应报道甚少.以手性伯胺硫脲作为催化剂,对蒽酮与硝基苯乙烯的不对称有机催化Michael加成反应进行了研究.实验结果表明,所用的伯胺硫脲均具有较好的催化活性(80%～95%收率),其中硫脲4a得到了较高的对映选择性.对反应条件进行优化后,以乙醚为溶剂,使用5%摩尔分数催化剂4a和苯甲酸,研究了多个硝基苯乙烯类底物和蒽酮的Michael加成反应,获得了优异的化学收率(95%～98%)和较好的对映选择性(最高86%ee).     

有机催化的不对称氧化反应

有机催化剂在不对称氧化反应中显示出巨大应用潜力. 综述了不同类型的有机催化剂催化的α,β-不饱和醛酮、烯烃的不对称环氧化反应及羰基化合物的不对称α-羟基化反应, 并对催化特点及催化机理作了详细的描述.     

Recent applications of mechanochemistry in enantioselective synthesis

In recent years, sustainable organocatalysis has become a relevant target in asymmetric organic synthesis. Among the most successful strategies to achieve “greener” organocatalyzed processes are (1) the elimination of solvent from reaction media, and (2) the use of alternative activation energies such as solvent-free mechanochemistry in high speed ball mills. In recent years we have stepped up efforts in the pursuit of organocatalysts and biocatalysts that allow reactions to take place in the absence of solvent and under mechanochemical activation. In this article we present the application of small dipeptides as chiral organocatalysts under solvent-free and high-speed ball milling conditions, with focus on the asymmetric aldol addition reaction. Finally, we report on recent results using supported enzymes for the resolution of racemic β-amino acids and amines, under mechanochemical conditions.     

微通道反应器在不对称催化中的应用

不对称催化是合成手性化合物的重要手段,针对该领域已开展了大量的研究工作并获得了引人瞩目的研究成果。相比于传统的釜式反应器,微通道反应器具有传质/传热效率高、反应时间短、易于自动化和提高安全性等优势。因此,将微通道反应器应用于不对称催化领域已成为当前的研究热点,并且在耦合在线分析、多相催化和光催化等领域已展现出良好的应用前景。本文对近年来微通道反应器在不对称催化领域中的最新研究进展进行总结和综述,并对未来的发展方向进行展望。     

Optically Controlled Recovery and Recycling of Homogeneous Organocatalysts Enabled by Photoswitches

We address a critical challenge of recovering and recycling homogeneous organocatalysts by designing photoswitchable catalyst structures that display a reversible solubility change in response to light. Initially insoluble catalysts are UV-switched to a soluble isomeric state, which catalyzes the reaction, then back-isomerizes to the insoluble state upon completion of the reaction to be filtered and recycled. The molecular design principles that allow for the drastic solubility change over 10 times between the isomeric states, 87 % recovery by the light-induced precipitation, and multiple rounds of catalyst recycling are revealed. This proof of concept will open up opportunities to develop highly recyclable homogeneous catalysts that are important for the synthesis of critical compounds in various industries, which is anticipated to significantly reduce environmental impact and costs.     

Small organic molecule catalyzed enantioselective direct aldol reaction in water

Protonated pyrrolidine based small organic molecules have been designed and evaluated for the asymmetric direct aldol reaction in water. The designed organocatalysts are multifunctional in nature and exploit the combined effect of hydrogen bonding and hydrophobic interactions for enantioselective catalysis in water. As a result a unique direct asymmetric aldol reaction in water catalyzed by a small organic molecule having an amide linkage has been developed. The developed catalyst affords chiral β-hydroxyketones in good yields (93%) and enantioselectivities (upto 62%) in water.     

Click反应和多氮化合物手性催化剂

Click化学涉及一系列能够在温和条件下高产率进行的有机反应, 已经被用来构建一些手性有机催化剂. 一些多氮化合物作为手性有机催化剂, 在反应过程中形成多重氢键使反应过渡态得以稳定, 显示出非常好的立体选择性.     

Pyrrolidine-based chiral pyridinium ionic liquids (ILs) as recyclable and highly efficient organocatalysts for the asymmetric Michael addition reactions

A novel series of pyrrolidine-based chiral pyridinium ionic liquids (ILs) have been developed by using commercially available (S)-(2-aminomethyl)-1-N-Boc-pyrrolidine. These chiral ILs have been found to be recyclable and efficient organocatalysts for the asymmetric catalytic Michael addition reactions of ketones to nitroolefins with high yields, high enantioselectivies, and diastereoselectivies.     

Reusable shuttles for exchangeable functional cargos: Reversibly assembled,magnetically powered organocatalysts for asymmetric aldol reactions

A supramolecular approach has been followed to support adamantyl substituted proline organocatalysts onto the surface of magnetite nanoparticles decorated with a β-cyclodextrin motif. The resulting magnetic nanoparticles (ca. ∼10 nm diameter) were used as modular, magnetically recyclable catalysts in the asymmetric aldol reaction of aromatic aldehydes with cyclic ketones in water. The catalytic assemblies can be easily dismantled in organic media, and the recovered nanoparticles (magnetically powered chemical shuttles) re-complexed with another suitably substituted catalytic unit (replaceable functional cargo).     

离子液体中的不对称催化反应*

对价格昂贵的手性催化剂进行回收和重复利用是目前不对称催化领域面临的难题之一,受到学术界和工业界的共同关注。化学家们已经尝试了许多方法,其中使用离子液体来替代常规有机溶剂使催化剂得到分离和重新使用已经引起他们极大的兴趣。本文综述了近年来在离子液体中进行不对称催化反应的研究进展,对离子液体中过渡金属和有机小分子催化的各种反应进行重点介绍,强调了离子液体不但在催化剂回收方面有独特优势,而且在许多反应中能够提高催化效率。     

Construction of Acyclic All-Carbon Quaternary Stereocenters and 1,3-Nonadjacent Stereoelements via Organo/Metal Dual Catalyzed Asymmetric Allenylic Substitution of Aldehydes

A method for the asymmetric construction of functionalized acyclic all-carbon quaternary stereocenters and 1,3-nonadjacent stereoelements has been developed via organo/metal dual catalyzed asymmetric allenylic substitution of branched and linear aldehydes, by developing an unknown acyclic secondary-secondary diamine as the enabling organocatalyst. Although it is believed that secondary-secondary diamines are difficult to be used as the organocatalysts in organo/metal dual catalysis, this study demonstrates that such diamines can be successfully combined with a metal catalyst in organo/metal dual catalysis. Our study enables the asymmetric construction of two important classes of motifs which were previously difficult to access, axially chiral allene-containing acyclic all-carbon quaternary stereocenters and 1,3-nonadjacent stereoelements bearing allenyl axial chirality and central chirality, in good yields with high enantio- and diastereoselectivity.