Recent developments in the supramolecular chemistry of terpyridine-metal complexes

This critical review describes recent developments in the field of supramolecular chemistry of terpyridine-metal complexes. The synthesis and characteristics of single as well as multiple homo- and heterometallic complexes is discussed. Furthermore, complexes containing fullerenes, biological building blocks, extended aggregates of different architectures as well as rings are presented. A special emphasis is placed upon the properties (e.g. redox properties, luminescence etc.) of functional systems. Potential applications in optical nano-devices, molecular storage units, molecular switches and solar cells are discussed.     

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.     

Palladium nanoparticles as efficient green homogeneous and heterogeneous carbon-carbon coupling precatalysts: a unifying view

Pd catalysis of C-C bond formations is briefly reviewed from the angle of nanoparticles (NPs) whether they are homogeneous or heterogeneous precatalysts and whether they are intentionally preformed or generated from a Pd derivative such as Pd(OAc)2. The most studied reaction is the Heck coupling of halogenoarenes with olefins that usually proceeds at high temperature (120-160 degrees C). Under such conditions, the PdII precursor is reduced to Pd0, forming PdNPs from which Pd atom leaching, subsequent to oxidative addition of the aryl halide onto the PdNP surface, is the source of very active molecular catalysts. Other C-C coupling reactions (Suzuki, Sonogashira, Stille, Negishi, Hiyama, Corriu-Kumada, Ullmann, and Tsuji-Trost) can also be catalyzed by species produced from preformed PdNPs. For catalysis of these reactions, leaching of active Pd atoms from the PdNPs may also provide a viable molecular mechanistic scheme. Thus, the term "PdNP catalysis of C-C coupling" used in this review refers to this function of PdNPs as precursors of catalytically active Pd species (i.e., the PdNPs are precatalysts of C-C coupling reactions).     

Recent advances in [2+2+2] cycloaddition reactions

The [2+2+2] cycloaddition is an elegant, atom-efficient and group tolerant process for the synthesis of carbo- and heterocycles, mostly aromatic, involving the formation of several C-C bonds in a single step. Cyclotrimerisation is catalyzed by a variety of organometallic complexes, including more than 15 different metals. The aim of this tutorial review is to point out the most recent advances in this field and to encourage the use of this reaction enroute to complex molecules. After summarizing the most common catalysts and reaction conditions generally used, we survey the mechanistic features currently accepted for this reaction. Section 4 covers the scope of the different [2+2+2] cycloaddition versions starting with the cyclotrimerisation of three triple bonds, including nitriles, with especial emphasis on asymmetric reactions that create central, axial or planar chirality. Then, reactions that use double bonds are addressed. Finally, the most outstanding examples of natural products synthesis using [2+2+2] cycloadditions as a key step reported recently are shown.     

Transition metal-catalyzed carbon-carbon bond activation

This tutorial review deals with recent developments in the activation of C-C bonds in organic molecules that have been catalyzed by transition metal complexes. Many chemists have devised a variety of strategies for C-C bond activation and significant progress has been made in this field over the past few decades. However, there remain only a few examples of the catalytic activation of C-C bonds, in spite of the potential use in organic synthesis, and most of the previously published reviews have dwelt mainly on the stoichiometric reactions. Consequently, this review will focus mainly on the catalytic reaction of C-C bond cleavage by homogeneous transition metal catalysts. The contents include cleavage of C-C bonds in strained and unstrained molecules, and cleavage of multiple C-C bonds such as C[triple bond]C triple bonds in alkynes. Multiple bond metathesis and heterogeneous systems are beyond the scope of this review, though they are also fascinating areas of C-C bond activation. In this review, the strategies and tactics for C-C bond activation will be explained.     

A resourceful new strategy in organic synthesis: Tandem and stepwise metathesis/non-metathesis catalytic processes

Highlighting the impressive potential of tandem and stepwise metathesis/non-metathesis reactions in synthesis, the present review extends the scope of the newly gained renown of metathesis as a progressive policy for advanced, elegant and economical organic synthesis. Background is provided for the most encountered to date applications where fundamental non-metathetical synthetic transformations (hydrogenation, oxidation, isomerization, allylation, cyclopropanation, etc.) and a variety of name reactions (Diels–Alder, Claisen, Heck, Ugi, Pauson–Khand, Kharasch addition, etc.) are occurring in tandem, as concurrent or sequential processes, with every known type of metathetical reactions catalyzed by ruthenium or molybdenum complexes.     

Decarboxylative coupling reactions: a modern strategy for C-C-bond formation

This critical review examines transition metal-catalyzed decarboxylative couplings that have emerged within recent years as a powerful strategy to form carbon-carbon or carbon-heteroatom bonds starting from carboxylic acids. In these reactions, C-C bonds to carboxylate groups are cleaved, and in their place, new carbon-carbon bonds are formed. Decarboxylative cross-couplings constitute advantageous alternatives to traditional cross-coupling or addition reactions involving preformed organometallic reagents. Decarboxylative reaction variants are also known for Heck reactions, direct arylation processes, and carbon-heteroatom bond forming reactions.     

Creating carbon-carbon bonds with samarium diiodide for the synthesis of modified amino acids and peptides

In this perspective, an overview of our experiences on the application of samarium diiodide in organic synthesis for the preparation of amino acid and peptide analogues is presented. Three different carbon-carbon bond forming reactions are discussed, including side chain introductions, gamma-amino acid synthesis and acyl-like radical additions for the construction of C-C mimics of the peptidic bonds.     

Tandem reactions initiated by copper-catalyzed cross-coupling: a new strategy towards heterocycle synthesis

Copper-catalyzed cross-coupling reactions which lead to the formation of C-N, C-O, C-S and C-C bonds have been recognized as one of the most useful strategies in synthetic organic chemistry. During past decades, important breakthroughs in the study of Cu-catalyzed coupling processes demonstrated that Cu-catalyzed reactions are broadly applicable to a variety of research fields related to organic synthesis. Representatively, employing these coupling transformations as key steps, a large number of tandem reactions have been developed for the construction of various heterocyclic compounds. These tactics share the advantages of high atom economics of tandem reactions as well as the broad tolerance of Cu-catalyst systems. Therefore, Cu-catalyzed C-X (X = N, O, S, C) coupling transformation-initiated tandem reactions were quickly recognized as a strategy with great potential for synthesizing heterocyclic compounds and gained worldwide attention. In this review, recent research progress in heterocycle syntheses using tandem reactions initiated by copper-catalyzed coupling transformations, including C-N, C-O, C-S as well as C-C coupling processes are summarized.     

Recent advances in the iron-catalysed multicomponent reactions

Iron-catalysed reactions are widely used in organic synthesis owing to its benefits over other metals. Among the important organic reactions, multicomponent reactions play a significant role due to its greener aspects like high atom economy, minimal amount of by-product, economic feasibility etc. For the past few years, iron-catalysed multicomponent reactions have attracted the attention of several chemists which lead to the invention of some fine chemistry. The majority of iron-catalysed multicomponent reactions results in the synthesis of heterocyclic compounds having biologically active natural products, pharmaceutical etc. These developments in the iron-catalysed multicomponent reactions are the focus of this review. This is the first review in this topic which covers the literature up to 2020, and it encompasses the different methods for the synthesis of acyclic, carbocyclic and heterocyclic compounds.     

Microwave-assisted C-C bond forming cross-coupling reactions: an overview

Among the fundamental transformations in the field of synthetic organic chemistry, transition-metal-catalyzed reactions provide some of the most attractive methodologies for the formation of C-C and C-heteroatom bonds. As a result, the application of these reactions has increased tremendously during the past decades and cross-coupling reactions became a standard tool for synthetic organic chemists. Furthermore, a tremendous upsurge in the development of new catalysts and ligands, as well as an increased understanding of the mechanisms, has contributed substantially to recent advances in the field. Traditionally, organic reactions are carried out by conductive heating with an external heat source (for example, an oil bath). However, the application of microwave irradiation is a steadily gaining field as an alternative heating mode since its dawn at the end of the last century. This tutorial review focuses on some of the recent developments in the field of cross-coupling reactions assisted by microwave irradiation.     

Palladium-catalyzed cross-coupling reactions of coumarin derivatives: An overview

Coumarins are omnipresent in several plants and exhibit a plethora of pharmacological properties, making them an important scaffold in organic synthesis. Naturally, the chemistry of this motif has attracted ever-increasing attention, among which palladium-catalyzed coupling reactions are the most prevalent one. Numerous useful, easy, and concise syntheses and reactions have been achieved using palladium-catalyzed coupling reactions. This review focuses on recent advances in palladium-catalyzed cross-coupling reactions such as Suzuki, Heck, Stille, Sonogoshira etc. reactions of coumarin derivatives and covers the literature from 2001 to 2020.     

Recent Advances in One-Pot Modular Synthesis of 2-Quinolones

It is known that 2-quinolones are broadly applicable chemical structures in medicinal and agrochemical research as well as various functional materials. A number of current publications about their synthesis and their applications emphasize the importance of these small molecules. The early synthetic chemistry originated from the same principle of the classical Friedländer and Knorr procedures for the preparation of quinolines. The analogous processes were developed by applying new synthetic tools such as novel catalysts, the microwave irradiation method, etc., whereas recent innovations in new bond forming reactions have allowed for novel strategies to construct the core structures of 2-quinolones beyond the bond disconnections based on two classical reactions. Over the last few decades, some reviews on structure-based, catalyst-based, and bioactivity-based studies have been released. In this focused review, we extensively surveyed recent examples of one-pot reactions, particularly in view of modular approaches. Thus, the contents are categorized as three major sections (two-, three-, and four-component reactions) according to the number of reagents that ultimately compose atoms of the core structures of 2-quinolones. The collected synthetic methods are discussed from the perspectives of strategy, efficiency, selectivity, and reaction mechanism.     

The production of carbon nanotubes from carbon dioxide:challenges and opportunities

Recent advances in the production of carbon nanotubes (CNTs) are reviewed with an emphasis on the use of carbon dioxide (CO2) as a sole source of carbon. Compared to the most widely used carbon precursors such as graphite, methane, acetylene, ethanol, ethylene, and coal-derived hydrocarbons, CO2 is competitively cheaper with relatively high carbon yield content. However, CNT synthesis from CO2 is a newly emerging technology, and hence it needs to be explored further. A theoretical and analytical comparison of the currently existing CNT-CO2 synthesis techniques is given including a review of some of the process parameters (i.e., temperature, pressure, catalyst, etc.) that affect the CO2 reduction rate. Such analysis indicates that there is still a fundamental need to further explore the following aspects so as to realize the full potential of CO2 based CNT technology: (1) the CNT-CO2 synthesis and formation mechanism, (2) catalytic effects of transitional metals and mechanisms, (3) utilization of metallocenes in the CNT-CO2 reactions, (4) applicability of ferrite-organometallic compounds in the CNT-CO2 synthesis reactions, and (5) the effects of process parameters such as temperature, etc.     

The production of carbon nanotubes from carbon dioxide: challenges and opportunities

Recent advances in the production of carbon nanotubes (CNTs) are reviewed with an emphasis on the use of carbon dioxide (CO2) as a sole source of carbon. Compared to the most widely used carbon precursors such as graphite, methane, acetylene, ethanol, ethylene, and coal-derived hydrocarbons, CO2 is competitively cheaper with relatively high carbon yield content. However, CNT synthesis from CO2 is a newly emerging technology, and hence it needs to be explored further. A theoretical and analytical comparison of the currently existing CNT-CO2 synthesis techniques is given including a review of some of the process parameters (i.e., temperature, pressure, catalyst, etc.) that affect the CO2 reduction rate. Such analysis indicates that there is still a fundamental need to further explore the following aspects so as to realize the full potential of CO2 based CNT technology: (1) the CNT-CO2 synthesis and formation mechanism, (2) catalytic effects of transitional metals and mechanisms, (3) utilization of metallocenes in the CNT-CO2 reactions, (4) applicability of ferrite-organometallic compounds in the CNT-CO2 synthesis reactions, and (5) the effects of process parameters such as temperature, etc.     

Transformations of diphenylphosphinothioic acid tertiary amides mediated by directed ortho metallation

ortho-Lithiation of N,N-diisopropyl-P,P-diphenylphosphinothioic amide using n-BuLi in the presence of TMEDA in diethyl ether followed by electrophilic trapping is described as an efficient method for the synthesis of ortho-functionalised derivatives in high yields. The structural modification of the phosphinothioic amide includes C-X (X = P, S, Si, Sn, I) and C-C bond forming reactions with a large variety of electrophiles. Additional applications based on functional group transformations are also reported. They include imine formation, desulfurization and Suzuki cross-coupling reactions on selected compounds.     

Enantioselective C-C bond synthesis catalysed by enzymes

The enantioselective synthesis of C-C bonds is often the pivotal step of a synthesis. Nature has made a variety of versatile enzymes available that catalyse this type of reaction very selectively under mild conditions. Cyanohydrins, acyloins (alpha-hydroxy ketones), alpha-hydroxy acids and aldols (beta-hydroxy ketones) are very efficiently synthesised enantioselectively with the aid of C-C bond forming enzymes, which we discuss in this tutorial review. In the case of the alpha-hydroxy acids the applications of nitrilases in a synthetic dkr even allows a disconnection that has no enantioselective chemical equivalent.     

一氧化碳加氢制碳氢化合物反应选择性的调控

合成气（即一氧化碳加氢）催化转化制碳氢化合物的费托合成反应是煤、甲烷和生物质等非油基碳资源间接转化制液体燃料或化学品的关键步骤．在传统的费托合成催化荆上,产物服从Anderson．Schulz．Flory分布,特定产物的选择性差．设计和制备高选择性费托合成催化剂,实现C-C偶联产物选择性的调控,是现代C,化学最具挑战性的课题．本文概述了近年来有关c￡偶联机理方面的理论研究进展,简要总结了影响费托合成产物选择性的几个关键因素,着重阐述了活性金属尺寸及所处微环境对产物选择性和催化：舌性的影响．本文还评述了既具有一氧化碳加氢制高碳烃又具有高碳烃加氢裂解能力的双功能费托合成催化剂体系,并提出通过控制加氢裂解等二次反应控制费托合成产物选择性的新策略．     

Fe和Co催化的碳-碳偶联反应的最新进展

作为廉价而且低毒的金属, Fe和Co是发展催化剂的理想元素. 同时由于Fe和Co有着多种氧化还原价态, 它们的催化化学应该具有极其丰富的内容. 然而由于种种原因, Fe和Co的催化剂很少得到有机化学家的关注. 直到最近几年, 人们才发现Fe和Co的催化剂可以很好地催化碳-碳偶联反应. 综述了Fe和Co催化碳-碳偶联反应的条件、产率和选择性; 探讨了这些新奇反应的可能机理; 并介绍了这些反应在复杂化合物合成中的应用.     

Enantioselective Addition of Diethylzinc to Aldehydes Catalyzed by N-Sulfonylated Amino Alcohols

Asymmetric C-C bond forming reactions are of prime importance in modem synthetic organic chemistry. The use of chiral amino alcohol ligands is widespread in this area.[1] Herein, we describe the synthesis of N-sulfonylated amino alcohols 1～4 and enantioselective addition of diethylzinc to aldehydes was carried out employing titanium(Ⅳ) complexes 1～4.