scholarly journals Multicomponent Reactions Involving Diazo Reagents: A 5-Year Update

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6563
Author(s):  
Olga Bakulina ◽  
Anna Inyutina ◽  
Dmitry Dar’in ◽  
Mikhail Krasavin
Keyword(s):  
Multicomponent Reactions ◽  
Diazo Compounds ◽  
Catalyst Free ◽  
Recent Developments ◽  
Diazo Reagents ◽  
Metal Catalyzed

This review summarizes recent developments in multicomponent reactions of diazo compounds. The role of diazo reagent and the type of interaction between components was analyzed to structure the discussion. In contrast to previous reviews on related topics mostly focused on metal catalyzed transformations, a substantial amount of organocatalytic or catalyst-free methodologies is covered in this work.

Recent Developments in the Synthetic Uses of Silyl-protected Enoldiazoacetates for Heterocyclic Syntheses

2014 ◽  
Vol 67 (3) ◽  
pp. 365 ◽  
Author(s):  
Xinfang Xu ◽  
Michael P. Doyle
Keyword(s):  
Heterocyclic Compounds ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
Diazo Compounds ◽  
Cycloaddition Reactions ◽  
Insertion Reactions ◽  
Active Compounds ◽  
The Core ◽  
Recent Developments ◽  
Metal Catalyzed

Diazo compounds have been used as precursors to a wide variety of heterocyclic compounds that represent the core structural subunits in many biologically active compounds. Various methodologies have been established for their synthesis via metal-catalyzed carbene transformations. Although the advantages of vinyldiazoacetates have been known for many years, realization of the synthetic use of enoldiazoacetates has been more recent. This review covers advances in the utility of silyl-protected enoldiazoacetates in heterocycle syntheses that include X–H insertion reactions, ylide rearrangements, formal [3+3]- and [4+3]-cycloaddition reactions, and other traditional and unusual metal carbene transformations.

scholarly journals Recent Advances in Rare Earth Complexes Containing N-Heterocyclic Carbenes: Synthesis, Reactivity, and Applications in Polymerization

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 71 ◽  
Author(s):  
Yu Pan ◽  
Xinxin Jiang ◽  
Yat-Ming So ◽  
Ching Tat To ◽  
Gaohong He
Keyword(s):  
Rare Earth ◽  
Catalytic Performance ◽  
Transition Metal Catalysts ◽  
Heterocyclic Carbenes ◽  
Unique Role ◽  
Ancillary Ligands ◽  
Grubbs Catalysts ◽  
Recent Developments ◽  
Metal Catalyzed

N-heterocyclic carbenes (NHCs) are ubiquitous ancillary ligands employed in metal-catalyzed homogeneous reactions and polymerization reactions. Of significance is the use of NHCs as the supporting ligand in second- and third-generation Grubbs catalysts for their application in olefin metathesis and ring-opening metathesis polymerization. While the applications of transition metal catalysts ligated with NHCs in polymerization chemistry are well-documented, the use of analogous rare earth (Ln = Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) catalysts in this area remains under-developed, despite the unique role of rare earth elements in regio- and stereo-specific (co)polymerization reactions. By using hetero-atom-tethered chelating NHCs and, more recently, the employment of other structurally related NHCs, NHC-ligated Ln complexes have proven to be promising and fruitful catalysts for selective polymerization reactions. This review summarizes the recent developments in the coordination chemistry of Ln complexes containing NHCs and their catalytic performance in polymerization.

How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans?

2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe
Keyword(s):  
Histone Modifications ◽  
Molecular Mechanisms ◽  
Epigenetic Inheritance ◽  
Nematode Caenorhabditis Elegans ◽  
Histone Methyltransferases ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Recent Developments ◽  
Gene Regulatory

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.

Wilfred Ethier. Modern International Economics. New York: W. W. Norton and Company. 1983. xviii + 588 pp.

1988 ◽  
Vol 27 (1) ◽  
pp. 81-83
Author(s):  
Nadeem A. Burney
Keyword(s):  
International Economic ◽  
New York ◽  
Economic Theory ◽  
International Economics ◽  
International Monetary System ◽  
International Markets ◽  
The Past ◽  
Monetary System ◽  
Recent Developments

Its been long recognized that various economies of the world are interlinked through international trade. The experience of the past several years, however, has demonstrated that this economic interdependence is far greater than was previously realized. In this context, the importance of international economic theory as an area distinct from general economics hardly needs any mentioning. What gives international economic theory this distinction is international markets for some goods and effects of national sovereignty on the character of economic activity. Wilfred Ethier's book, which incorporates recent developments in the field, is an excellent addition to textbooks on international economics for one- or twosemester undergraduate courses. The book mostly covers standard topics. A distinguishing feature of this book is its detailed analysis of the flexible exchange rates and a discussion of the various approaches used for their determination. Within each chapter, the author has extensively used facts, figures and major events to clarify the concepts in the light of the theoretical framework. The book also discusses, in a fair amount of detail, the existing international monetary system and the role of various international organizations.

Organic Reactivity Control by Means of Neighboring Groups and Organometallics. A Personal Account

1994 ◽  
Vol 59 (1) ◽  
pp. 1-74 ◽  
Author(s):  
Pavel Kočovský
Keyword(s):  
Transition Metals ◽  
Cyclopropane Ring ◽  
Allylic Substitutions ◽  
Recent Developments ◽  
Cardioactive Drug ◽  
Novel Method ◽  
Metal Catalyzed ◽  
Electrophilic Additions ◽  
Near Future ◽  
First Time

This review summarizes the main topics of our research and covers the period of the last 15 years. The prime interest is focused on various ways of controlling the regio- and stereoselectivity of selected organic reactions, in particular electrophilic additions, cleavage of cyclopropane rings, and allylic substitutions by means of neighboring groups and/or transition and non-transition metals. In the first part, the factors governing the course of electrophilic additions are assessed, culminating in the formulation of selection rules for the reactivity of cyclohexene systems, and in a concise synthesis of the natural cardioactive drug, strophanthidin. These studies also contribute to a better understanding of the mechanisms of electrophilic additions. The second part describes recent developments in the stereo- and regiocontrolled cleavage of cyclopropane rings by non-transition metals (Tl and Hg), and the reactivity and transmetalation (with Pd) of the primary products. This methodology has resulted in novel routes to unique polycyclic structures, and will have synthetic applications in the near future. Evidence for the stereospecific "corner" cleavage of the cyclopropane ring has been provided for the first time for Tl and later for Hg. The third part deals with transition metal-catalyzed allylic substitution. Evidence for a new "syn" mechanism for the formation of the intermediate (π-allyl)palladium complex has been provided, which runs counter to the generally accepted "anti" mechanism. A novel method for a Pd-catalyzed allylic oxidation has been developed and employed in the synthesis of natural sesquiterpenes. The increasing importance of transition and non-transition metals for synthetic organic chemistry is demonstrated by their unique reactivity in a number of the papers included in this review.

The Role of Financial Innovation in EU Market Integration and the Capital Markets Union

2018 ◽  
Author(s):  
Emilios Avgouleas
Keyword(s):  
Capital Markets ◽  
Risk Sharing ◽  
Market Integration ◽  
Financial Innovation ◽  
The European Union ◽  
Recent Developments ◽  
Capital Markets Union ◽  
Critical Overview ◽  
The Eu

This chapter offers a critical overview of the issues that the European Union 27 (EU-27) will face in the context of making proper use of financial innovation to further market integration and risk sharing in the internal financial market, both key objectives of the drive to build a Capital Markets Union. Among these is the paradigm shift signalled by a technological revolution in the realm of finance and payments, which combines advanced data analytics and cloud computing (so-called FinTech). The chapter begins with a critical analysis of financial innovation and FinTech. It then traces the EU market integration efforts and explains the restrictive path of recent developments. It considers FinTech's potential to aid EU market integration and debates the merits of regulation dealing with financial innovation in the context of building a capital markets union in EU-27.

scholarly journals Russia’s Foreign Policy Evolution in the New Balkan Landscape

2020 ◽  
Vol 56 (3-4) ◽  
pp. 179-199
Author(s):  
Ekaterina Entina ◽  
Alexander Pivovarenko
Keyword(s):  
Foreign Policy ◽  
Soviet Union ◽  
Regional Security ◽  
Southeast Europe ◽  
The Balkans ◽  
Current Trends ◽  
The Soviet Union ◽  
Recent Developments ◽  
The Difference

The article reflects on the issue of the foreign policy strategy of modern Russia in the Balkans region. One of the most significant aspects of this problem is the difference in views between Russia and the West. Authors show how different interpretations of the events in former Yugoslavia in the 1990s and the beginning of the 2000s predetermined the sense of mutual suspicion and mistrust which spread to other regions such as the post-Soviet space. Exploring differences between the Russian and the Western (Euro-Atlantic) views on the current matters, authors draw attention to fundamental differences in terminology: while the Western narrative promotes more narrow geographical and political definitions (such as the Western Balkan Six), traditional Russian experts are more inclined to wider or integral definitions such as “the Balkans” and “Central and Southeast Europe”. Meanwhile none of these terms are applicable for analysis of the current trends such as the growing transit role of the Balkans region and its embedding in the European regional security architecture. Therefore, a new definition is needed to overcome the differences in vision and better understand significant recent developments in the region. Conceptualizing major foreign policy events in Central and Southeast Europe during the last three decades (the 1990s, 2000s and 2010s), authors demonstrate the significance of differences in tools and methods between the Soviet Union and the modern Russia. Permanent need for adaptation to changing political and security context led to inconsistence in Russian Balkan policy in the 1990s. Nevertheless, Russia was able to preserve an integral vision of the region and even to elaborate new transregional constructive projects, which in right political circumstances may promote stability and become beneficial for both Russia and the Euro-Atlantic community.

scholarly journals Negativity and Political Behavior: A Theoretical Framework for the Analysis of Negative Voting in Contemporary Democracies

2021 ◽  
pp. 147892992110001
Author(s):  
Diego Garzia ◽  
Frederico Ferreira da Silva
Keyword(s):  
Public Opinion ◽  
Political Behavior ◽  
Voting Behavior ◽  
Theoretical Framework ◽  
Negative Attitudes ◽  
Affective Component ◽  
Parliamentary Systems ◽  
Recent Developments ◽  
Rational Component

Recent developments in Western societies have motivated a growing consideration of the role of negativity in public opinion and political behavior research. In this article, we review the scant (and largely disconnected) scientific literature on negativity and political behavior, merging contributions from social psychology, public opinion, and electoral research, with a view on developing an integrated theoretical framework for the study of negative voting in contemporary democracies. We highlight that the tendency toward negative voting is driven by three partly overlapping components, namely, (1) an instrumental–rational component characterized by retrospective performance evaluations and rationalization mechanisms, (2) an ideological component grounded on long-lasting political identities, and (3) an affective component, motivated by (negative) attitudes toward parties and candidates. By blueprinting the systematic relationships between negative voting and each of these components in turn, and suggesting multiple research paths, this article aims to stimulate future studies on negative voting in multi-party parliamentary systems to motivate a better understanding of the implications of negativity in voting behavior in contemporary democracies.

Ambivalent role of ascorbic acid in the metal-catalyzed oxidation of oligopeptides

2021 ◽  
pp. 111510
Author(s):  
Nikolett Bodnár ◽  
Katalin Várnagy ◽  
Lajos Nagy ◽  
Gizella Csire ◽  
Csilla Kállay
Keyword(s):  
Ascorbic Acid ◽  
Metal Catalyzed Oxidation ◽  
Metal Catalyzed ◽  
Catalyzed Oxidation

scholarly journals Recent Developments on Five-Component Reactions

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1986
Author(s):  
Xiaoming Ma ◽  
Sanjun Zhi ◽  
Wei Zhang
Keyword(s):  
Multicomponent Reactions ◽  
High Efficiency ◽  
Review Article ◽  
Reaction Centers ◽  
Synthetic Approach ◽  
Recent Developments

Multicomponent reactions (MCRs) have inherent advantages in pot, atom, and step economy (PASE). This important green synthetic approach has gained increasing attention due to high efficiency, minimal waste, saving resources, and straightforward procedures. Presented in this review article are the recent development on 5-compoment reactions (5CRs) of the following six types: (I) five different molecules A + B + C + D + E; pseudo-5CRs including (II) 2A + B + C + D, (III) 2A + 2B + C, (IV) 3A + B + C, (V) 3A + 2B, and (VI) 4A + B. 5CRs with more than five-reaction centers are also included.

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