Cinchona alkaloid-based chiral catalysts act as highly efficient multifunctional organocatalysts for the asymmetric conjugate addition of malonates to nitroolefins

2015 ◽  
Vol 13 (40) ◽  
pp. 10216-10225 ◽  
Author(s):  
Veeramanoharan Ashokkumar ◽  
Ayyanar Siva
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Conjugate Addition ◽  
Quaternary Ammonium Salts ◽  
Cinchona Alkaloid ◽  
Ammonium Salts ◽  
Addition Reactions ◽  
Chiral Catalysts ◽  
Reaction Conditions ◽  
Highly Efficient

New pentaerythritol tetrabromide based chiral quaternary ammonium salts have been prepared and used as organocatalysts for enantioselective Michael addition reactions between various nitroolefins and Michael donors under mild reaction conditions with very good chemical yields and ee's.

Highly enantioselective Michael addition reactions with new trimeric chiral phase transfer catalysts

2015 ◽  
Vol 39 (4) ◽  
pp. 3098-3104 ◽  
Author(s):  
Arockiam Jesin Beneto ◽  
Jayaraman Sivamani ◽  
Veeramanoharan Ashokkumar ◽  
Rajendiran Balasaravanan ◽  
Kumaraguru Duraimurugan ◽  
...  
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Phase Transfer ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Addition Reactions ◽  
Chiral Phase ◽  
Catalytic Activities ◽  
Phase Transfer Catalysts ◽  
Chiral Phase Transfer Catalysts

New types of mesitylene based tri-site containing asymmetric quaternary ammonium salts 9 (9a and 9b) were synthesized and their catalytic activities were studied using Michael addition reactions with various chalcones and diethylmalonate under mild basic conditions with very good yields and ee's.

scholarly journals A Remarkably Efficient Phase-Transfer Catalyzed Amination of α-Bromo-α, β-Unsaturated Ketones in Water

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Alemayehu Mekonnen ◽  
Alemu Tesfaye
Keyword(s):  
Quaternary Ammonium ◽  
Phase Transfer ◽  
Conjugate Addition ◽  
Quaternary Ammonium Salts ◽  
Cinchona Alkaloids ◽  
Ammonium Salts ◽  
Alkylation Reaction ◽  
Pt Catalysts ◽  
Unsaturated Ketones ◽  
Catalytic Performances

Tandem conjugate addition–alkylation reaction of various amines with α-bromo-α, β-unsaturated ketones resulted in near-quantitative conversions into the corresponding aziridines when the reaction was carried out in the presence of 10 mol% of phase-transfer, PT catalysts in water. Some chiral quaternary ammonium salts derived from Cinchona alkaloids were investigated as water-stable PT catalysts. The scope and limitations of the reaction have also been investigated. The catalytic performances were significantly improved in comparison with the corresponding ordinary quaternary ammonium salt catalysts, and excellent yields (81%–96%) were obtained. Although an increase in the rate of aziridination has been accomplished, no stereoselectivity was observed. The positive values of the protocol have been confirmed.

Highly Efficient Aza-Michael Reactions of Enones with Carbamates Using a Combination of Quaternary Ammonium Salts and BF3×OEt2 as a Catalyst.

ChemInform ◽  
2004 ◽  
Vol 35 (15) ◽  
Author(s):  
Li-Wen Xu ◽  
Lyi Li ◽  
Chun-Gu Xia ◽  
Shao-Lin Zhou ◽  
Jing-Wei Li ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Highly Efficient ◽  
Michael Reactions
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