新型吡咯酰胺催化剂的设计合成及催化Knoevenagel反应

合成了5种未见报道的手性吡咯酰胺类有机小分子催化剂,并催化Knoevenagel反应.生成的烯腈产率高达80％以上,有机小分子催化剂回收率高达85％以上,可以重复使用,其催化活性并未降低.     

有机催化不对称aza-Henry反应研究进展

不对称aza-Henry反应是重要的碳碳键形成反应,手性产物β-硝基胺是许多药物和天然产物的关键中间体,利用该反应构建手性化合物已有广泛报道,其中有机催化不对称aza-Henry反应已成为不对称催化领域的重要研究对象。催化不对称aza-Henry反应的有机小分子催化剂主要有硫脲类催化剂和相转移催化剂,其中硫脲类催化剂占主要部分,其次还有方酰胺类、胍酰胺类以及脲类等催化剂。对近5年有机催化不对称aza-Henry反应的发展现状进行概述并作出总结与展望,以期为今后有机催化不对称合成研究提供参考。     

有机双功能团小分子催化剂的研究进展

在过去的10年时间里,有机小分子催化剂作为一门环境友好的有机合成方法学在不对称催化合成中的应用得到了重新发掘,新颖的有机小分子催化剂受到广泛的关注。其中,有机双功能团小分子催化剂的分子中存在两个活性位点同时和底物相互作用,导致了反应速率的加快和立体选择性的提高,成为国内外的研究热点。本文简要介绍了近几年来有机双功能团催化剂的研究进展,包括联二萘酚为母体的B rφnsted酸催化剂、硫脲催化剂及奎宁催化剂。     

有机催化不对称Henry反应研究进展

Henry是一个重要的人名反应,在有机合成中具有广泛的应用。分别概述了醛、酮化合物和硝基烷烃在有机小分子催化作用下的不对称Henry反应,以及有机催化的不对称串联Michael/Henry反应。对于胍、硫脲、胺、相转移催化剂及奎宁衍生物(类似物)等不同类型有机小分子催化不对称Henry反应作了概述。并对有机催化不对称Henry反应的研究作了相应的展望。     

不对称Michael加成反应研究进展

随着有机小分子催化不对称有机合成反应的发展,人们设计出了大量的手性有机小分子催化剂并对于有机小分子催化的不对称Michael加成也进行了大量的研究。本文综述了近年来国内外不同研究小组对不对称Michael加成的研究进展,并对不同催化剂在不对称Michael加成反应中的应用进行了简单的评述。     

有机小分子催化α，β-不饱和酮的不对称共轭加成反应研究进展

不饱和酮的不对称共轭加成反应在有机合成中是一类连接C-C键的非常重要的反应。相比过渡金属催化,有机小分子催化剂有着独特的优势,如不含过渡金属、容易制备、价格低廉、反应条件温和以及稳定性强等。文章综述了几类有机小分子催化剂对α,β-不饱和酮的不对称共轭加成反应。结果表明,手性胺和手性磷酸催化剂在不对称加成中具有良好的收率及选择性,但是包含联萘酚骨架的催化剂对于大部分的共轭加成反应均具有优秀的催化作用以及优异的选择性。     

逆向相转移催化（IPTC）

相转移催化宜加速各种介面间的反应,包括小分子反应、聚合物合成和聚合物修饰等。迄今所用的相转移催化剂都是将水溶性或固体的反应物转入有机相。Mathias等提出了一新型的反应,它是将溶于有机相的反应物转入水     

不对称催化合成手性泛解酸内酯的研究进展

泛解酸内酯是合成D-泛酸钙和D-泛醇的重要中间体,国内主要采用生物拆分法,虽取得一定进展,但存在底物浓度偏低、反应条件苛刻、光学纯度不高和催化剂活性不强等问题。化学不对称合成法成为近年来制备手性泛内酯的研究热点。根据手性源的不同,介绍过渡金属配合物催化不对称还原酮基泛内酯,过渡金属配合物催化羟醛缩合反应,有机小分子及其衍生物不对称催化羟醛缩合反应并经还原内酯化合成泛内酯以及光学活性化合物作为反应底物或非手性底物中加入手性助剂的合成手性泛内酯工艺。其中,有机小分子催化乙醛酸酯与醛的反应表现出良好的催化效果,且催化剂易得,反应条件温和,操作简单。缩合产物的收率和对映选择性均不高,设计具有高活性和高选择性的有机小分子手性催化剂是今后研究的重点。     

氢键诱导的不对称催化反应研究进展

氢键催化在不对称有机催化领域已经有了重大进展.手性有机小分子通过氢键活化羰基化合物和亚胺等得到极大的关注.主要对手性硫脲和二醇催化剂的氢键催化进行综述.重点介绍不同手性硫脲和二醇催化剂的催化活性及其在各类不对称催化反应中(包括不对称Strecker反应、Pictet-Spengler反应、Mannich反应、Baylis-Hillman反应、Diels-Alder反应以及Michael反应)的催化效果.     

L-脯氨酸在有机合成中的应用研究进展

L-脯氨酸是一种具有活性强、立体专一性好、来源广泛、价格便宜、环境友好等特点的小分子有机催化剂.综述了L-脯氨酸在Al?dol反应、Knoevenagel反应、Mannich反应、Michael加成反应等有机合成中的应用研究进展.     

Theory of asymmetric organocatalysis of Aldol and related reactions: rationalizations and predictions

Computational studies have led to models to understand some classic and contemporary asymmetric reactions involving organocatalysts. The Hajos-Parrish-Eder-Sauer-Wiechert reaction and intermolecular aldol reactions as well as Mannich reactions and oxyaminations catalyzed by proline and other amino acids, and Diels-Alder reactions catalyzed by MacMillan's chiral amine organocatalysts have been studied with density functional theory. Quantitative predictions for several new catalysts and reactions are provided.     

L‐Prolinethioamides – Efficient Organocatalysts for the Direct Asymmetric Aldol Reaction

A series of novel L ‐proline derived thioamides has been synthesised. They have been evaluated as organocatalysts in the direct asymmetric aldol reaction for the first time. Thioamides exhibit catalytic ability higher than proline itself and the model aldol reaction of 4‐cyanobenzaldehyde with acetone proceeds well in the presence of 5 mol % of catalyst (ee up to 100%). Other aromatic aldehydes gave aldol products with high ees and moderate yields. Small changes in the catalyst's structure [e.g., N‐Bn versus N‐CH(CH₃)Ph] as well as the addition of an acid have a profound effect on their activity. The unexpected formation of the catalyst‐derived cyclic adducts was observed and their reactivity was established giving valuable insight into the course of the reaction.     

Advances in Immobilized Organocatalysts for the Heterogeneous Asymmetric Direct Aldol Reactions

The aim of this article is to collect the results published from the beginning (2000) on asymmetric direct aldol reactions taking place in the presence of immobilized chiral organocatalysts. The seven groups of organocatalysts discussed are: asymmetric direct aldol reactions catalyzed by: (1) covalently bonded immobilized hydroxyproline organocatalysts; (2) covalently bonded immobilized prolinamide organocatalysts; (3) covalently bonded immobilized peptide organocatalysts; (4) other covalently bonded immobilized chiral organocatalysts; (5) chiral organocatalysts bonded by ionic groups; (6) chiral organocatalysts with adsorptive bonding; and (7) other types of immobilized chiral organocatalysts. The main objective of this article based on results obtained by using about 360 immobilized organocatalysts, to bring to the focus of catalyst systems in which the aldol reactions yield beta-hydroxyketones of maximal optical purity, while keeping catalyst concentrations and reaction times as low and as short as possible. Trends recognized in data obtained in this field of investigation may mark out further tasks for the purpose of practical application.     

A New Family of Conformationally Constrained Bicyclic Diarylprolinol Silyl Ethers as Organocatalysts

Simple chemical manipulations of trans‐4‐L ‐hydroxy proline allow the access to a new family of bicyclic silyl ether organocatalysts that display some remarkable features. Apart from being extremely stable to hydrolytic conditions and possessing excellent catalytic performances, the rigidity of the bicyclic structure imposes a synclinal endo disposition of the bulky substituents with respect to the pyrrolidine ring, opposed to the more stable synclinal exo conformations of Jørgensen–Hayashi catalysts.     

Highly Enantioselective Transfer Hydrogenation of α‐Imino Esters by a Phosphoric Acid

Chiral phosphoric acids have been identified as highly efficient organocatalysts for the asymmetric transfer hydrogenation of α‐imino esters and amide. Utilizing Hantzsch esters as the hydrogen donor, versatile highly enantioenriched α‐amino esters and their derivatives were obtained with up to 98 % ee.     

Update and challenges in organo-mediated polymerization reactions

Organocatalysis has become a very powerful tool for precision macromolecular chemistry, as judged by the number of articles published in this field in the past decade. A variety of small organic molecules, including Brønsted/Lewis bases and acids, based on amines, phosphines or carbenes, but also on bi-component systems, have been employed as a means to catalyze the polymerization of miscellaneous monomers. Not only can organocatalysts be employed to promote the ring-opening polymerization of various heterocyclics (e.g. lactones, lactide, cyclic carbonates, epoxides, lactams, cyclocarbosiloxanes), but some of them also allow activating vinylic monomers such as (meth)acrylics, or triggering the step-growth polymerization of monomers such as diisocyanates and diols for polyurethane synthesis. The reduced toxicity of organocatalysts in comparison to their metallic counterparts is also driving their development in some sensitive applications, such as biomedical or microelectronics. Overall, organocatalysts display specific monomer activation modes, thereby providing a unique opportunity to control the polymerization of various functional monomers, under mild conditions. This review article focuses on advances of the past 4 years (>150 publications) in polymerization reactions utilizing small organic molecules either as direct initiators or as true catalysts, with a special emphasis on monomer activation modes, as well as polymerization mechanism aspects.     

Organocatalytic asymmetric epoxidation of olefins by chiral ketones

Chiral ketones have been shown to be effective organocatalysts for asymmetric epoxidation of olefins with broad substrate scope. High enantioselectivity has been obtained for a wide variety of trans and trisubstituted olefins, as well as a number of cis olefins, with encouragingly high ee's for some terminal olefins. The stereochemical outcome of the reaction can be rationalized by a spiro transition state model.     

The enantioselective synthesis of alpha-amino acids by phase-transfer catalysis with achiral Schiff base esters

The development and application of chiral phase-transfer catalysis (PTC) for the enantioselective synthesis of optically active alpha-amino acid derivatives using achiral Schiff base esters developed in the author's laboratory and by others is reviewed. Phase-transfer catalysts derived from the Cinchona alkaloids have been exploited as inexpensive and attractive organocatalysts in the chiral PTC process. The recent evolution and use of these and other catalytic systems is described.     

Chiral Amino Diol Derivatives as New Modular Organocatalysts for the Enantioselective α‐Chlorination of Cyclic β‐Keto Esters

Highly modular chiral amino diol derivatives have been used as organocatalysts in the enantioselective α‐chlorination of cyclic β‐keto esters. Optimization of the catalyst structure and the reaction conditions has allowed the synthesis of optically active α‐chlorinated products with high enantioselectivities (up to 96% ee) using inexpensive commercially available N‐chlorosuccinimide (NCS) as the chlorine source under mild conditions.     

Asymmetric synthesis of fluorine-containing compounds using organocatalysts

Asymmetric synthesis of fluorine-containing compounds using organocatalysts has been extensively investigated and several important strategies have been developed in the last decade. This review focuses on the recent advances in the introduction of the fluorine atom into organic molecules by: i) electrophilic fluorination reactions; ii) the use of easily available fluorine-containing building blocks, both of interest in our research laboratory.