ChemInform Abstract: Enantioselective Stetter Reactions of Enals and Modified Chalcones Catalyzed by N-Heterocyclic Carbenes.

ChemInform ◽  
2012 ◽  
Vol 43 (19) ◽  
pp. no-no
Author(s):  
Xinqiang Fang ◽  
Xingkuan Chen ◽  
Hui Lv ◽  
Yonggui Robin Chi
Keyword(s):  
Heterocyclic Carbenes ◽  
Stetter Reactions

Kinetic Resolution, Dynamic Kinetic Resolution and Asymmetric Desymmetrization by N-Heterocyclic Carbene Catalysis

Synthesis ◽  
2019 ◽  
Vol 51 (09) ◽  
pp. 1871-1891 ◽  
Author(s):  
Carmela De Risi ◽  
Olga Bortolini ◽  
Graziano Di Carmine ◽  
Daniele Ragno ◽  
Alessandro Massi
Keyword(s):  
Kinetic Resolution ◽  
Stereoselective Synthesis ◽  
Short Review ◽  
Heterocyclic Carbenes ◽  
Dynamic Kinetic Resolution ◽  
Asymmetric Transformations ◽  
Significant Interest ◽  
Stetter Reactions

N-Heterocyclic carbenes (NHCs) are now well-established organocatalysts for a large number of asymmetric and non-asymmetric transformations. In the last 15 years, there has been significant interest in using NHCs in kinetic resolution (KR), dynamic kinetic resolution (DKR) and asymmetric desymmetrization reactions for the stereoselective synthesis of enantioenriched compounds, with diverse substrates and activation modes being adopted to this end. This short review brings into focus the progress made on NHC-catalyzed KR, DKR, and asymmetric desymmetrization from 2004 until December 2018. The literature discussed in this article is classified on the basis of the type of reaction involving the NHC catalyst.1 Introduction2 Acylation Strategies2.1 O-Acylation2.2 N-Acylation2.3 C-Acylation3 Aldol-Acylation Processes4 Benzoin Reactions5 Stetter Reactions6 Miscellaneous Approaches7 Conclusion

Enantioselective Stetter Reactions of Enals and Modified Chalcones Catalyzed by N-Heterocyclic Carbenes

2011 ◽  
Vol 123 (49) ◽  
pp. 11986-11989 ◽  
Author(s):  
Xinqiang Fang ◽  
Xingkuan Chen ◽  
Hui Lv ◽  
Yonggui Robin Chi
Keyword(s):  
Heterocyclic Carbenes ◽  
Stetter Reactions

Enantioselective Stetter Reactions of Enals and Modified Chalcones Catalyzed by N-Heterocyclic Carbenes

2011 ◽  
Vol 50 (49) ◽  
pp. 11782-11785 ◽  
Author(s):  
Xinqiang Fang ◽  
Xingkuan Chen ◽  
Hui Lv ◽  
Yonggui Robin Chi
Keyword(s):  
Heterocyclic Carbenes ◽  
Stetter Reactions

Aryl-substituted Triarsiranes: Synthesis and Reactivity

2020 ◽  
Author(s):  
André Schumann ◽  
Jonas Bresien ◽  
Malte Fischer ◽  
Christian Hering-Junghans
Keyword(s):  
Organic Chemistry ◽  
Electronic Structure ◽  
Heterocyclic Carbenes ◽  
Synthetic Approaches ◽  
Inorganic And Organic

Cyclotriarsanes are rare and limited synthetic approaches have hampered reactivity studies on these systems. Described in here is a scalable synthetic protocol towards (AsAr)<sub>3</sub> (Ar = Dip, 2,6-<sup>i</sup>Pr<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>; Tip, 2,4,6-<sup>i</sup>Pr<sub>3</sub>-C<sub>6</sub>H<sub>2</sub>), which allowed to study their reactivity towards [Cp<sub>2</sub>Ti(C<sub>2</sub>(SiMe<sub>3</sub>)<sub>2</sub>], affording titanocene diarsene complexes and towards N-heterocyclic carbenes (NHCs) to give straightforward access to a variety of NHC-arsinidene adducts. The electronic structure of the titanium diarsene complxes has been studied and they are best described as Ti(IV) species with a doubly reduced As<sub>2</sub>Ar<sub>2</sub> ligand. These findings will make (AsAr)<sub>3</sub> valuable precursors in the synthetic inorganic and organic chemistry.

Application of Nitrogen Heterocyclic Carbenes in Organocatalysis

2020 ◽  
Vol 09 ◽  
Author(s):  
Minita Ojha ◽  
R. K. Bansal
Keyword(s):  
Asymmetric Catalysis ◽  
Building Blocks ◽  
Structural Features ◽  
Heterocyclic Carbenes ◽  
Stetter Reaction ◽  
Metal Pollutants ◽  
Synthetic Strategy ◽  
Wide Range ◽  
Benzoin Condensation ◽  
Nitrogen Heterocyclic

Background: During the last two decades, horizon of research in the field of Nitrogen Heterocyclic Carbenes (NHC) has widened remarkably. NHCs have emerged as ubiquitous species having applications in a broad range of fields, including organocatalysis and organometallic chemistry. The NHC-induced non-asymmetric catalysis has turned out to be a really fruitful area of research in recent years. Methods: By manipulating structural features and selecting appropriate substituent groups, it has been possible to control the kinetic and thermodynamic stability of a wide range of NHCs, which can be tolerant to a variety of functional groups and can be used under mild conditions. NHCs are produced by different methods, such as deprotonation of Nalkylhetrocyclic salt, transmetallation, decarboxylation and electrochemical reduction. Results: The NHCs have been used successfully as catalysts for a wide range of reactions making a large number of building blocks and other useful compounds accessible. Some of these reactions are: benzoin condensation, Stetter reaction, Michael reaction, esterification, activation of esters, activation of isocyanides, polymerization, different cycloaddition reactions, isomerization, etc. The present review includes all these examples published during the last 10 years, i.e. from 2010 till date. Conclusion: The NHCs have emerged as versatile and powerful organocatalysts in synthetic organic chemistry. They provide the synthetic strategy which does not burden the environment with metal pollutants and thus fit in the Green Chemistry.

scholarly journals Sydnone methides – a forgotten class of mesoionic compounds for the generation of anionic N‐heterocyclic carbenes

2021 ◽  
Author(s):  
Andreas Schmidt ◽  
Sebastian Mummel ◽  
Felix Lederle ◽  
Eike Hübner ◽  
Jan C. Namyslo ◽  
...  
Keyword(s):  
Heterocyclic Carbenes
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