ChemInform Abstract: Cinchona Alkaloid Catalyzed Sulfa-Michael Addition Reactions Leading to Enantiopure β-Functionalized Cysteines.

ChemInform ◽  
2016 ◽  
Vol 47 (11) ◽  
pp. no-no
Author(s):  
Arjen C. Breman ◽  
Suze E. M. Telderman ◽  
Roy P. M. van Santen ◽  
Jamie I. Scott ◽  
Jan H. van Maarseveen ◽  
...  
Keyword(s):  
Michael Addition ◽  
Cinchona Alkaloid ◽  
Addition Reactions

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.

scholarly journals Novel Selenoureas Based on Cinchona Alkaloid Skeleton: Synthesis and Catalytic Investigations

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 600
Author(s):  
Mariola Zielińska-Błajet ◽  
Joanna Najdek
Keyword(s):  
Michael Addition ◽  
Catalytic Performance ◽  
Cinchona Alkaloid ◽  
Addition Reactions ◽  
Efficient Approach ◽  
Mild Conditions ◽  
Asymmetric Michael Addition

An efficient approach to the synthesis of chiral selenoureas consisting of Cinchona alkaloid scaffolds was described. The new selenoureas were assessed as bifunctional organocatalysts in the asymmetric Michael addition reactions under mild conditions. The best results were obtained for selenoureas bearing the 4-fluorophenyl group. These catalysts promoted the reactions with enantioselectivities of up to 96% ee. Additionally, the catalytic performance of the thiourea and selenourea counterpart was compared.

Thia-Michael Addition Reactions in Water Using 3-[Bis(Alkylthio) Methylene] Pentane-2,4-Diones as Odorless and Efficient Thiol Equivalents

2007 ◽  
Vol 4 (4) ◽  
pp. 281-284 ◽  
Author(s):  
Yanyan Chai ◽  
Dewen Dong ◽  
Yan Ouyang ◽  
Yongjiu Liang ◽  
Yan Wang ◽  
...  
Keyword(s):  
Michael Addition ◽  
Addition Reactions

scholarly journals Recoverable Phospha-Michael Additions Catalyzed by a 4-N,N-Dimethylaminopyridinium Saccharinate Salt or a Fluorous Long-Chained Pyridine: Two Types of Reusable Base Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1159
Author(s):  
Eskedar Tessema ◽  
Vijayanath Elakkat ◽  
Chiao-Fan Chiu ◽  
Jing-Hung Zheng ◽  
Ka Long Chan ◽  
...  
Keyword(s):  
Michael Addition ◽  
Polar Solvent ◽  
Addition Reaction ◽  
High Yield ◽  
Addition Reactions ◽  
Polar Solvents ◽  
Unsaturated Bond ◽  
Base Catalysts ◽  
Michael Additions

Phospha-Michael addition, which is the addition reaction of a phosphorus-based nucleophile to an acceptor-substituted unsaturated bond, certainly represents one of the most versatile and powerful tools for the formation of P-C bonds, since many different electrophiles and P nucleophiles can be combined with each other. This offers the possibility to access many diversely functionalized products. In this work, two kinds of basic pyridine-based organo-catalysts were used to efficiently catalyze phospha-Michael addition reactions, the 4-N,N-dimethylaminopyridinium saccharinate (DMAP·Hsac) salt and a fluorous long-chained pyridine (4-Rf-CH2OCH2-py, where Rf = C11F23). These catalysts have been synthesized and characterized by Lu’s group. The phospha-Michael addition of diisopropyl, dimethyl or triethyl phosphites to α, β-unsaturated malonates in the presence of those catalysts showed very good reactivity with high yield at 80–100 °C in 1–4.5 h with high catalytic recovery and reusability. With regard to significant catalytic recovery, sometimes more than eight cycles were observed for DMAP·Hsac adduct by using non-polar solvents (e.g., ether) to precipitate out the catalyst. In the case of the fluorous long-chained pyridine, the thermomorphic method was used to efficiently recover the catalyst for eight cycles in all the reactions. Thus, the easy separation of the catalysts from the products revealed the outstanding efficacy of our systems. To our knowledge, these are good examples of the application of recoverable organo-catalysts to the DMAP·Hsac adduct by using non-polar solvent and a fluorous long-chained pyridine under the thermomorphic mode in phospha-Michael addition reactions.

Highly Stereoselective Michael Addition Reactions of CamTHP*-Desymmetrized Glycinamide for the Synthesis of Functionally Dense Amino Acid Derivatives

2004 ◽  
Vol 6 (24) ◽  
pp. 4427-4429 ◽  
Author(s):  
Darren J. Dixon ◽  
Richard A. J. Horan ◽  
Nathaniel J. T. Monck ◽  
Paul Berg
Keyword(s):  
Amino Acid ◽  
Michael Addition ◽  
Amino Acid Derivatives ◽  
Addition Reactions

The first peripherally masked thiol dendrimers: a facile and highly efficient functionalization strategy of polyester dendrimers via one-pot xanthate deprotection/thiol–acrylate Michael addition reactions

2014 ◽  
Vol 50 (50) ◽  
pp. 6574-6577 ◽  
Author(s):  
Sam E. R. Auty ◽  
Oliver Andrén ◽  
Michael Malkoch ◽  
Steven P. Rannard
Keyword(s):  
Michael Addition ◽  
Addition Reactions ◽  
One Pot ◽  
Highly Efficient

We present the first xanthate surface functional dendrimers which undergo rapid one-pot deprotection to thiols and subsequent acrylate Michael addition .

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