Highly Enantioselective Addition of Enals to Isatin-Derived Ketimines Catalyzed by N-Heterocyclic Carbenes: Synthesis of Spirocyclic γ-Lactams

2012 ◽  
Vol 14 (21) ◽  
pp. 5412-5415 ◽  
Author(s):  
Hui Lv ◽  
Bhoopendra Tiwari ◽  
Junming Mo ◽  
Chong Xing ◽  
Yonggui Robin Chi
Keyword(s):  
Heterocyclic Carbenes ◽  
Enantioselective Addition

ChemInform Abstract: Highly Enantioselective Addition of Enals to Isatin-Derived Ketimines Catalyzed by N-Heterocyclic Carbenes. Synthesis of Spirocyclic γ-Lactams.

ChemInform ◽  
2013 ◽  
Vol 44 (11) ◽  
pp. no-no
Author(s):  
Hui Lv ◽  
Bhoopendra Tiwari ◽  
Junming Mo ◽  
Chong Xing ◽  
Yonggui Robin Chi
Keyword(s):  
Heterocyclic Carbenes ◽  
Enantioselective Addition

Regio-, Stereo- and Enantioselective α-Addition of Carbonyl Nucleo-philes to Allenamides Catalyzed by a Synergistic Copper/Enamine System

2020 ◽  
Author(s):  
Rémi Blieck ◽  
Sebastien Lemouzy ◽  
Marc Taillefer ◽  
Florian Monnier
Keyword(s):  
Catalytic System ◽  
Secondary Amine ◽  
Primary Amine ◽  
Synergistic Catalysis ◽  
Enantioselective Addition ◽  
Amine Catalysts

A dual copper/enamine catalytic system is found to enable an intermolecular enantioselective α-addition of various carbonyl nucleophiles to allenamides. Secondary amine catalysts allowed the highly enantioselective addition of aldehydes, while using primary amine catalysts led to the enantioselective addition of ketoester nucleophiles. The process was found to be highly regio-, stereo- and enantio-selective and represented the first allene hydrofunctionalization using an synergistic catalysis involving copper

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.

Highly enantioselective addition of sulfur-containing heterocycles to isatin-derived ketimines

2019 ◽  
Vol 17 (31) ◽  
pp. 7309-7314 ◽  
Author(s):  
Michael Franc ◽  
Michal Urban ◽  
Ivana Císařová ◽  
Jan Veselý
Keyword(s):  
Heterocyclic Compounds ◽  
Stereoselective Addition ◽  
Enantioselective Addition ◽  
Sulfur Containing

In this study, we report a highly stereoselective addition of sulfur-containing heterocyclic compounds to isatin-derived ketimines efficiently catalyzed by cinchonidine-derived bifunctional tertiary aminothiourea (1 mol%).

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

Dimethylzinc-mediated enantioselective addition of terminal alkynes to 1,2-diketones using perhydro-1,3-benzoxazines as ligands

2021 ◽  
Author(s):  
Elena Prieto ◽  
Rebeca Infante ◽  
Javier Nieto ◽  
Celia Andres
Keyword(s):  
Chiral Ligand ◽  
Terminal Alkynes ◽  
Conformationally Restricted ◽  
Enantioselective Addition

A conformationally restricted perhydro-1,3-benzoxazine derived from (-)-8-aminomenthol behaves as a good chiral ligand in the dimethylzinc-mediated enantioselective monoaddition of aromatic and aliphatic terminal alkynes to 1,2-diketones. The corresponding α-hydroxyketones were...

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