Iron catalyzed stereoselective alkene synthesis: a sustainable pathway

2020 ◽  
Vol 56 (95) ◽  
pp. 14937-14961
Author(s):  
Xin-Fang Duan

Replacing expensive or toxic transition metals with iron has become an important trend. This article summarises the recent progresses of a wide range of Fe-catalyzed reactions for accessing various stereodefined alkenes.

2020 ◽  
Vol 24 (3) ◽  
pp. 231-264 ◽  
Author(s):  
Kevin H. Shaughnessy

Phosphines are widely used ligands in transition metal-catalyzed reactions. Arylphosphines, such as triphenylphosphine, were among the first phosphines to show broad utility in catalysis. Beginning in the late 1990s, sterically demanding and electronrich trialkylphosphines began to receive attention as supporting ligands. These ligands were found to be particularly effective at promoting oxidative addition in cross-coupling of aryl halides. With electron-rich, sterically demanding ligands, such as tri-tertbutylphosphine, coupling of aryl bromides could be achieved at room temperature. More importantly, the less reactive, but more broadly available, aryl chlorides became accessible substrates. Tri-tert-butylphosphine has become a privileged ligand that has found application in a wide range of late transition-metal catalyzed coupling reactions. This success has led to the use of numerous monodentate trialkylphosphines in cross-coupling reactions. This review will discuss the general properties and features of monodentate trialkylphosphines and their application in cross-coupling reactions of C–X and C–H bonds.


2021 ◽  
Vol 29 (1) ◽  
pp. 6-11
Author(s):  
Valentina A. Maslova ◽  

The article deals with the status of the speech genres theory (SGT) and its contribution to the development of modern linguistics. In his polemical article Professor V. V. Dementyev argues that SGT is characterized by the wide range of research problems, a close connection with such academic domains as the theory of speech acts, colloquial studies, discourse analysis, linguistic personology and other areas that study a human and their language. This thesis does not raise objections, as the 21st century is considered to be the century of syncretism and interpenetration of sciences, which has become one of the main features of the entire post-non-classical science. This approach provides a holistic reflection on the object of study, in this case, on the language. It is called syncretism, integrity, interdisciplinarity, polydisciplinarity, transdisciplinarity. In general, these terms are synonymous, because they are based on the idea of holism of everything in the world. In this sense, SGT is in line with modern science. The thesis of V. V. Dementyev on the diffusion of genres. Diffusion can be considered as the most important trend not only in science, but also in the entire modern culture, which is shown with the help of examples. However, some statements of V. V. Dementyev’s article seem debatable: the problem of the pervasiveness of SGT in linguistics in its entirety, which can give rise to a dangerous tendency – the absorption of linguistics by SGT. Their interests do often overlap, but each of the named areas solves the problem of personal communication in a social environment in its own way, and each of them has its own subject and its own history. Today SGT cannot take into account many of the processes occurring in discourse, but this is a relatively new science with a great future.


Life ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Michael S. Wang ◽  
Kenric J. Hoegler ◽  
Michael H. Hecht

Life as we know it would not exist without the ability of protein sequences to bind metal ions. Transition metals, in particular, play essential roles in a wide range of structural and catalytic functions. The ubiquitous occurrence of metalloproteins in all organisms leads one to ask whether metal binding is an evolved trait that occurred only rarely in ancestral sequences, or alternatively, whether it is an innate property of amino acid sequences, occurring frequently in unevolved sequence space. To address this question, we studied 52 proteins from a combinatorial library of novel sequences designed to fold into 4-helix bundles. Although these sequences were neither designed nor evolved to bind metals, the majority of them have innate tendencies to bind the transition metals copper, cobalt, and zinc with high nanomolar to low-micromolar affinity.


2021 ◽  
Author(s):  
Xiao-Feng Wu ◽  
Tim Meyer ◽  
Robert Franke ◽  
Hui-Qing Geng

Hydroformylation catalyzed by transition metals is one of the most important homogeneously catalyzed reactions in industrial organic chemistry. Millions of tons of aldehydes and related chemicals are produced by this...


2021 ◽  
Author(s):  
Yatheesh Narayana ◽  
Sandhya N. C. ◽  
H.E. Dinesh ◽  
Sridhar B. Thimmaiah ◽  
Kanchugarakoppal S. Rangappa ◽  
...  

Arduengo et al., isolated the first ‘bottleable’ carbene, the first N-heterocyclic carbene (NHC) 1,3-di(adamantyl)imidazol-2-ylidene resulted to an explosion of experimental and theoretical studies of novel NHCs being synthesized and analyzed have huge practical significance. These compounds emerged as successful ligands for coordinating transition metals, the complexes with NHC show diverse applications in the field of catalysis and organic transformation, NHC as ligand to main group elements and their properties and applications. Here this chapter provides the concise overview of N-heterocycle carbene as an organocatalyst that provides different organic transformation on to a carbonyl group. The majority of the NHC catalyzed reactions are employed in the phenomenon of reversing the electrophilic character of carbonyl carbon to nucleophilic carbon (umpolung activity) on coordination suggests benzoin, Stetter and hydroacylation reactions. Also, non-umpolung activity of bis-electrophile α,β-unsaturated acylazoliums reaction with suitable bis-nucleophiles in the organic synthesis have been studied.


Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5346
Author(s):  
J. M. Ramirez-de-Arellano ◽  
M. Canales ◽  
L. F. Magaña

The adsorption of molecules usually increases capacity and/or strength with the doping of surfaces with transition metals; furthermore, carbon nanostructures, i.e., graphene, carbon nanotubes, fullerenes, graphdiyne, etc., have a large specific area for gas adsorption. This review focuses on the reports (experimental or theoretical) of systems using these structures decorated with transition metals for mainly pollutant molecules’ adsorption. Furthermore, we aim to present the expanding application of nanomaterials on environmental problems, mainly over the last 10 years. We found a wide range of pollutant molecules investigated for adsorption in carbon nanostructures, including greenhouse gases, anticancer drugs, and chemical warfare agents, among many more.


2018 ◽  
Vol 15 (8) ◽  
pp. 1124-1146 ◽  
Author(s):  
Navjeet Kaur

Background: The synthesis of N-polyheterocycles by environmentally benign method is highly attractive but challenging proposition. New strategies have been developed for the preparation of polycyclic heterocycles in the last decades. In this review article, the synthesis of nitrogen containing six-membered polycyclic heterocyclic compounds is presented with the application of ionic liquids. This contribution focuses on the literature related to the total synthesis of six-membered N-polyheterocycles. Objective: Ionic liquids not only acted as environmentally benign reaction media but also as catalysts which afforded the very promising replacements of traditional molecular solvents in organic chemistry due to their stability, non-flammability, non-volatility and ease of recyclability. Ionic liquids are utilized in metal catalyzed reactions in place of organic solvents in the last years. It has attracted considerable attention in recent years. Ionic liquids acted as alternatives of organic solvents and these ILs are environment friendly. Conclusion: In the area of green chemistry ionic liquid assisted synthesis is a very promising technique which afforded a flexible platform for the formation of heterocycles. The influence of ILs on the development of efficient and new synthetic protocols over the last decade for the construction of N-polyheterocycles is featured in this review article. These synthetic strategies will continue to attract more attention and will find a wide range of applications in organic synthesis. In conclusion, ionic liquids assisted syntheses have become an efficient and powerful tool in organic chemistry quickly.


2021 ◽  
Vol 258 ◽  
pp. 06046
Author(s):  
Tatiana Kharlamova ◽  
Andrey Kharlamov ◽  
Peter Lemeshchenko

The article examines the changes in the requirements for the development and implementation of innovations in the process of forming and improving supply chains in the face of increasing economic instability. Economic instability is presented as the most important trend in the modern economy and significant factor forming new requirements for supply chains. This, in turn, involves the improvement of applied technologies and development of new technologies, as well as the search for progressive technical and managerial solutions to meet the interests of a wide range of business entities and consumers of goods and services. A distinctive feature of this study is the fact that economic instability is viewed by the authors through the prism of both economic and non-economic processes having, inter alia, an impact on the economic system, including political, military, environmental, epidemiological and other processes. The article focuses on the COVID-19 coronavirus pandemic, as well as its impact on logistics solutions, and the specific demands on supply chains. It is substantiated that the introduction of technical and managerial innovations in this area will allow us to take into account the features and consequences of the impact of COVID-19 on the economy and to effectively influence the processes associated with improving supply chains. Thus, it will ensure compliance with the requirements and conditions determined by modern conditions associated with increased economic instability.


Synthesis ◽  
2022 ◽  
Author(s):  
Yu Ma ◽  
Ze-Yu Tian ◽  
Shuang-Yang Zheng ◽  
Cheng-Pan Zhang

Cyclopropyldiphenylsulfonium salt is a famous ylide precursor that was previously extensively employed in the preparation of cyclic compounds and has been successfully utilized as an efficient allylation reagent in this work. The Cu-catalyzed reactions of cyclopropyldiphenylsulfonium trifluoromethanesulfonate with amines in the presence of an appropriate ligand provided the N-allylated products in good yields. Aliphatic/aromatic amines and primary/secondary amines were all mildly converted under the reaction conditions. This protocol was also applicable to N-functionalization of drug molecules, supplying the corresponding N-allylated compounds in satisfactory yields. The reaction showed good functional group tolerance, a wide range of substrates, and excellent chemoselectivity, which offered an interesting method for the synthesis of N-allyl amines.


2015 ◽  
Vol 3 (14) ◽  
pp. 3422-3427 ◽  
Author(s):  
Fredrik Silvearv ◽  
Peter Larsson ◽  
Sarah. L. T. Jones ◽  
Rajeev Ahuja ◽  
J. Andreas Larsson

We have studied a wide range of transition metals to find potential carbon nanotube (CNT) catalysts for chemical vapor deposition (CVD) production.


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