N-Heterocyclic Carbene-Organocatalyzed Arene Formation: Application in Atroposelective Synthesis of Polysubstituted Benzenes

Synlett ◽  
2020 ◽  
Vol 31 (10) ◽  
pp. 925-932 ◽  
Author(s):  
Tingshun Zhu ◽  
Ke Xu ◽  
Ziyuan Wang
Keyword(s):  
Organic Chemistry ◽  
Recent Work ◽  
Organic Synthesis ◽  
Heterocyclic Carbenes ◽  
Powerful Method ◽  
Recent Developments ◽  
History Of ◽  
Cyclic Compounds ◽  
Near Future

In recent decades, organocatalysis by N-heterocyclic carbenes (NHCs) has emerged as a versatile and powerful method in organic synthesis. As a result of the power of NHC organocatalysis to produce cyclic compounds, polysubstituted benzenes, which are among the most important cyclic compounds in organic chemistry, can be synthesized efficiently and selectively. This article briefly summarizes the history of NHC organocatalysis, including recent developments in benzene-formation methods, and highlights our recent work in atroposelective arene formation by carbene-catalyzed formal [4+2] cyclo­additions. We expect that more NHC-catalyzed methods for the synthesis of asymmetric arenes will be developed in the near future, providing shortcuts to syntheses of sophisticated chiral functional molecules with polysubstituted benzene nuclei.

scholarly journals N-Heterocyclic Carbene Catalysis under Oxidizing Conditions

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 549 ◽  
Author(s):  
Krzysztof Dzieszkowski ◽  
Zbigniew Rafiński
Keyword(s):  
Organic Chemistry ◽  
Biological Activity ◽  
Organic Synthesis ◽  
Heterocyclic Carbenes ◽  
Natural Product Synthesis ◽  
Cooperative Catalysis ◽  
Cyclic Compounds ◽  
Synthetic Approaches ◽  
Further Development ◽  
Vast Range

N-heterocyclic carbene organocatalysis under oxidizing conditions provides a vast range of various synthetic procedures via diverse mechanisms. The available catalysts, bases, oxidants, and oxidizing methods afford numerous opportunities for developing this branch of organocatalysis. Furthermore, implementation of tandem reactions and cooperative catalysis in the described methodology significantly expands the possibilities of modern organic chemistry. This approach allows the synthesis of different structurally complex and often enantiomerically enriched substances, which can be interesting in terms of biological activity and natural product synthesis. Many esters, amides, thioesters, lactams, lactones, and other cyclic compounds obtained in oxidative or oxygenative reactions promoted by N-heterocyclic carbenes can be interesting precursors in advanced organic synthesis. Sophistication and broad applicability prove that the described synthetic approaches are exceptionally worthy of further development.

scholarly journals Applications of transition metal catalyzed P-radical for synthesis of organophosphorus compounds

2019 ◽  
Vol 91 (1) ◽  
pp. 87-94 ◽  
Author(s):  
Wei Ren ◽  
Qiang Yang ◽  
Shang-Dong Yang
Keyword(s):  
Transition Metal ◽  
Recent Work ◽  
Organic Synthesis ◽  
Organophosphorus Compounds ◽  
Powerful Method ◽  
Unsaturated Compounds ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

Abstract Phosphorus-radical participated difunctionalization reactions with unsaturated compounds have been recognized as powerful method for organic synthesis. This review covers our recent work on the application of transition metal catalyzed P-radical promoted difunctionalization for synthesis of organophosphorus compounds.

scholarly journals N-Heterocyclic carbene/Brønsted acid cooperative catalysis as a powerful tool in organic synthesis

2012 ◽  
Vol 8 ◽  
pp. 398-402 ◽  
Author(s):  
Rob De Vreese ◽  
Matthias D’hooghe
Keyword(s):  
Organic Chemistry ◽  
Organic Synthesis ◽  
Stereoselective Synthesis ◽  
Heterocyclic Carbenes ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Heterocyclic Chemistry ◽  
The Past ◽  
Cooperative Catalysis ◽  
Brönsted Acid

The interplay between metals and N-heterocyclic carbenes (NHCs) has provided a window of opportunities for the development of novel catalytic strategies within the past few years. The recent successful combination of Brønsted acids with NHCs has added a new dimension to the field of cooperative catalysis, enabling the stereoselective synthesis of functionalized pyrrolidin-2-ones as valuable scaffolds in heterocyclic chemistry. This Commentary will briefly highlight the concept of N-heterocyclic carbene/Brønsted acid cooperative catalysis as a new and powerful methodology in organic chemistry.

Organic Synthesis

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Organic Chemistry ◽  
Organic Synthesis ◽  
Synthetic Method ◽  
New Methods ◽  
Recent Developments ◽  
Asymmetric Organocatalysis

Organic synthesis is a vibrant and rapidly evolving field; we can now cyclize amines directly onto alkenes. Like its predecessors, this reference leads readers quickly to the field's more important recent developments. Two years of Douglass F. Taber's popular weekly online column, "Organic Chemistry Highlights", as featured on the organic-chemistry.org website, are consolidated here, with cumulative indices of all four volumes in this series. Important topics that are covered range from powerful new methods for C-C bond construction to asymmetric organocatalysis and direct C-H functionalization. This go-to reference focuses on the most important recent developments in organic synthesis, and includes a succinct analysis of the significance and applicability of each new synthetic method.

Organic Synthesis

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Organic Chemistry ◽  
Organic Synthesis ◽  
State Of The Art ◽  
Synthetic Method ◽  
Total Syntheses ◽  
New Methods ◽  
Recent Developments ◽  
Asymmetric Organocatalysis

Organic synthesis is a vibrant and rapidly evolving field; we can now cyclize amines directly onto alkenes. Like the first two books in this series, Organic Synthesis: State of the Art 2003-2005 and Organic Synthesis: State of the Art 2005-2007, this reference leads readers quickly to the most important recent developments. Two years of Taber's popular weekly online column, "Organic Chemistry Highlights", as featured on the organic-chemistry.org website, are consolidated here, with cumulative indices of all three volumes in this series. Important topics that are covered range from powerful new methods for C-C bond construction to asymmetric organocatalysis and direct C-H functionalization. This go-to reference focuses on the most important recent developments in organic synthesis, and includes a succinct analysis of the significance and applicability of each new synthetic method. It details and analyzes more than twenty complex total syntheses, including the Sammakia synthesis of the Macrolide RK-397, the Ley synthesis of Rapamycin, and the Kobayashi synthesis of (-)-Norzoanthamine.

Boron–nitrogen doped carbon scaffolding: organic chemistry, self-assembly and materials applications of borazine and its derivatives

2015 ◽  
Vol 51 (83) ◽  
pp. 15222-15236 ◽  
Author(s):  
Davide Bonifazi ◽  
Francesco Fasano ◽  
M. Mercedes Lorenzo-Garcia ◽  
Davide Marinelli ◽  
Hamid Oubaha ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Organic Synthesis ◽  
Self Assembly ◽  
Feature Article ◽  
Nitrogen Doped ◽  
The Past ◽  
Recent Developments ◽  
Nitrogen Doped Carbon ◽  
Boron Nitrogen

In this feature article we describe the past and recent developments in the organic synthesis and functionalisation of borazine, the isostructural inorganic analogue of benzene.

scholarly journals INTIMACY IN MODERN BRITISH HISTORY

2020 ◽  
pp. 1-16
Author(s):  
GEORGE MORRIS
Keyword(s):  
Recent Work ◽  
Historical Analysis ◽  
British History ◽  
Conceptual Clarity ◽  
Modern Britain ◽  
Recent Developments ◽  
History Of

Abstract Recent developments in the history of modern Britain have led to the emergence of a history of intimacy, whether or not it is recognized as such. This historiographical review argues that intimacy is a useful category of historical analysis. Thinking in terms of inter-relationships between different forms of intimacy allows us to think with greater conceptual clarity about these forms, as well as types of intimacy that are difficult to categorize. The first section reviews recent and significant contributions to the literature and seeks to draw out existing connections and crosscurrents between subfields. The second section turns to recent work on the histories of selfhood and the emotions and considers what thinking about intimacy might add to these fields; it then builds on this recent work to propose that one way to ‘do’ the history of intimacy is to think in terms of ‘intimate practices’.

scholarly journals The magnetic observatory on Tatuoca, Belém, Brazil: history and recent developments

2017 ◽  
Vol 6 (2) ◽  
pp. 367-376 ◽  
Author(s):  
Achim Morschhauser ◽  
Gabriel Brando Soares ◽  
Jürgen Haseloff ◽  
Oliver Bronkalla ◽  
José Protásio ◽  
...  
Keyword(s):  
Data Access ◽  
Research Centre ◽  
Small Island ◽  
Magnetic Observatory ◽  
Geomagnetic Equator ◽  
Time Data ◽  
Recent Developments ◽  
History Of ◽  
Near Future ◽  
Scientific Return

Abstract. The Tatuoca magnetic observatory (IAGA code: TTB) is located on a small island in the Amazonian delta in the state of Pará, Brazil. Its location close to the geomagnetic equator and within the South Atlantic Anomaly offers a high scientific return of the observatory's data. A joint effort by the National Observatory of Brazil (ON) and the GFZ German Research Centre for Geosciences (GFZ) was undertaken, starting from 2015 in order to modernise the observatory with the goal of joining the INTERMAGNET network and to provide real-time data access. In this paper, we will describe the history of the observatory, recent improvements, and plans for the near future. In addition, we will give some comments on absolute observations of the geomagnetic field near the geomagnetic equator.

scholarly journals The Magnetic Observatory on Tatuoca, Belém, Brazil: History and Recent Developments

2017 ◽  
Author(s):  
Achim Morschhauser ◽  
Gabriel Brando Soares ◽  
Jürgen Haseloff ◽  
Oliver Bronkalla ◽  
José Protasio ◽  
...  
Keyword(s):  
Data Access ◽  
Research Centre ◽  
Small Island ◽  
Magnetic Observatory ◽  
Geomagnetic Equator ◽  
Time Data ◽  
Recent Developments ◽  
History Of ◽  
Near Future ◽  
Scientific Return

Abstract. The Tatuoca magnetic observatory (IAGA code: TTB) is located on a small island in the Amazonian delta in the state Pará of Brazil. Its location close to the geomagnetic equator and within the South Atlantic Magnetic Anomaly offers a high scientific return of the observatory's data. A joint effort by Observatorio Nacional, Brazil (ON) and the GFZ German Research Centre for Geosciences (GFZ) was undertaken starting from 2015 in order to modernize the observatory with the goal to join the INTERMAGNET network and to provide real-time data access. In this paper, we will describe the history of the observatory, recent improvements, and plans for the near future. In addition, we will give some comments on absolute observations of the geomagnetic field near the geomagnetic equator.

Recent developments in automated Transmission Electron MI

1989 ◽  
Vol 47 ◽  
pp. 46-47
Author(s):  
W.J. de Ruijter ◽  
P. Rez ◽  
David J. Smith
Keyword(s):  
Image Analysis ◽  
Computer Image ◽  
Lens Design ◽  
Computer Image Analysis ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Recent Developments ◽  
On Line ◽  
Routine Procedures ◽  
Near Future

There is growing interest in the on-line use of computers in high-resolution electron n which should reduce the demands on highly skilled operators and thereby extend the r of the technique. An on-line computer could obviously perform routine procedures hand, or else facilitate automation of various restoration, reconstruction and enhan These techniques are slow and cumbersome at present because of the need for cai micrographs and off-line processing. In low resolution microscopy (most biologic; primary incentive for automation and computer image analysis is to create a instrument, with standard programmed procedures. In HREM (materials researc computer image analysis should lead to better utilization of the microscope. Instru (improved lens design and higher accelerating voltages) have improved the interpretab the level of atomic dimensions (approximately 1.6 Å) and instrumental resolutior should become feasible in the near future.

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