过渡金属催化异腈参与的多组分反应研究进展

综述介绍了近5年来过渡金属催化下异腈参与的多组分反应的研究进展.     

Recent advances in heterogeneous catalysts for the synthesis of imidazole derivatives

Among the bioactive heterocyclic frameworks, nitrogen containing multisubstituted imidazoles are versatile building blocks of many naturally occurring products. Imidazoles possess wide range of biological properties including anticancer, anti-inflammatory, antimicrobial, and antihypertensive activities with potential applications in other sectors. Multicomponent reactions in combination with heterogeneous catalysts and nanocomposites have contributed significantly to organic synthesis in general and imidazoles, in particular with high functional group tolerance. Owing to their tunable properties, lower operational cost, thermal stability, recyclability, and easily separation from products, heterogeneous catalysts and nanocomposites are integral part of numerous pharmaceutical, agrochemical, and industrial processes. There has been increased focus on the development of green and sustainable catalytic procedures for the building of novel and biologically potent imidazole conjugates. This article emphasizes the recent advances in recyclable catalysts and protocols, and their merits for the synthesis of diverse multisubstituted imidazole conjugates by one-pot reaction approach and the catalyst and reactant interactions.     

Recent advances in asymmetric multicomponent reactions (AMCRs)

Asymmetric multicomponent reactions (AMCRs) include the reaction of three or more reactants simultaneously to produce chiral products that they have some advantages containing simple procedures, saving time and energy, and being environmentally friendly processes. AMCRs have seen much development and their potent synthetic approaches are discussed in this review.     

Heterocycles as key substrates in multicomponent reactions: the fast lane towards molecular complexity

Heterocycles display an intrinsic reactivity which enables rich, versatile and productive transformations. Taking into account their ubiquitous presence in natural products and drugs, the development of new, fast and efficient preparative protocols for these structures remains an urgent task in Organic Synthesis. Multicomponent reactions using heterocyclic chemistry offer new possibilities to exploit this exclusive reactivity. Recent results show relevant examples of such transformations. Several approaches which allow the construction of complex heterocyclic compounds from simple starting materials using this principle have been analyzed.     

Organocatalytic multicomponent alpha-methylenation/Diels-Alder reactions: a versatile route to substituted cyclohexenecarbaldehyde derivatives

This article describes the design and optimization of an effective organocatalytic three-component domino alpha-methylenation/Diels-Alder reaction to produce vinyl-substituted cyclohexenecarboxaldehydes in a highly regioselective fashion. In these one-pot transformations, 2-formyl-1,3-butadienes (4) were prepared in situ from alpha,beta-unsaturated aldehydes and formalin and were subsequently trapped with a variety of buta-1,3-dienes. The outcomes of the reactions were dependent on the electronic properties of the dienes. 1-Vinylcyclohexenecarbaldehydes 6 were formed by use of acyclic electron-rich dienes, while the initially formed cycloadducts of 4 with cyclopentadiene underwent Cope rearrangements, leading to the formation of tetrahydro-3H-indene-5-carbaldehyde compounds 7. The mechanisms involved in these reactions were deduced from experimental findings. Furthermore, the method was also extended to one-pot domino methylenation/Diels-Alder reactions of dihydrofurans and dihydropyrans to yield spirocyclic lactols 22. In these reactions, the unstable intermediate hydroxyethyl and hydroxypropyl acroleins behaved as dienophiles, undergoing cycloaddition reactions with dienes with good yields and selectivities. The wide variety of functionalized 1-vinylcyclohex-3-enecarbaldehydes 6, 4-vinylcyclohex-1-enecarbaldehydes 7, and spiro lactols 22 generated through the use of these organocatalytic domino processes as a diversity-oriented synthesis provided useful intermediates for the construction of novel odorants.     

Innovative macromolecular syntheses via isocyanide multicomponent reactions

Isocyanide multicomponent reactions assemble more than two reaction components by exploiting the reactivity of the isocyanide carbon atom toward addition of electrophiles and nucleophiles. Reactions such as the Passerini three‐component and Ugi four‐component coupling reactions have a long and successful history in organic synthesis, which has only recently been explored in polymer chemistry. In a short time, this class of multicomponent reactions has been established as a viable method for the synthesis of linear polymers as well as more complex architectures such as miktoarm star polymers and dendrimers. This highlight discusses the recent accomplishments made with regard to innovative syntheses of polymers and dendrimers via the Passerini and Ugi reactions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3985–3991     

Recent Progress in the Catalytic Synthesis of Imidazoles

Imidazole is one of the important heteroaromatic compounds that have found a broad range of uses in, for example, pharmaceutical and industrial applications. Several conventional methodologies for the synthesis of imidazole rings are known; however, they are limited in terms of substrate generality and are not always efficient. Recent studies toward the development of catalytic reactions have brought significant improvements to the preparation of imidazoles. This Focus Review highlights the very recent progress in the catalytic synthesis of imidazoles, particularly those involving the formation of five‐membered ring cores.     

多组分反应合成杂环化合物研究进展

利用多组分反应合成结构复杂多样的杂环化合物,在有机合成领域具有广阔的应用前景和研究价值.本文综述了近年来多组分反应在五元杂环、六元杂环、多元杂环合成中的研究进展,同时对杂环化合物的绿色合成方法做出展望.     

Synthesis of enantiomerically pure cyclohex-2-en-1-ols: development of novel multicomponent reactions

Multicomponent reactions of aldehydes, dienophiles, and alcohols or carboxylic acid anhydrides have been developed for the first time. In situ generation of 1-acyloxy- and 1-alkoxy-1,3-butadiene derivatives in toluene in the presence of electron-deficient dienophiles provides selective and efficient access to functionalized cyclohex-2-ene-1-ols in good yields. Subsequent enzyme-catalyzed kinetic resolution gave the corresponding enantiomers with high enantioselectivity.     

催化不对称反应新发展: 不对称活化

介绍了催化不对称催化反应中的一个新概念－不对称活化(asymmetricactivation)及其研究的最新发展。运用不对称活化策略,一个光学活性的整或者甚至外消旋的催化剂可以被另一种手性活化剂(chiralactivator)选择性的活化,从而催化反应生成非外消旋产物。该方法较不对称活化(asymmetricactivation)方法的优点是被活化的催化剂能够产生较使用光学纯催化剂更高对映体过量的产物。     

Recent advances towards catalytic asymmetric Conia-ene-type reactions

Conia-ene reactions,as a type of ene reactions,have not become a remarkable focus until the beginning of21~(st) century,when Lewis acids served as powerful catalysts and found an increasingly broad utilization in this field.Consequently,the catalytic Conia-ene reactions have gained great significance in synthetic chemistry due to their high efficiency and atom economy on the construction of valuable cyclic molecules.During the past two decades,the rapid development of transition-metal catalysis and organocatalysis has imposed a profound impact on the exploration of asymmetric Conia-ene reactions.As a result,several strategies have been developed and applied successfully.Organized on the basis of the catalytic system,this review comprehensively presents a summary of recent progress achieved in this emerging domain,aimed at highlighting the reactions' features,practicalities,and the mechanistic rationale is presented where possible.