Designing Chiral Quaternary Ammonium Polymers: Novel Type of Polymeric Catalyst for Asymmetric Alkylation Reaction

2010 ◽  
Vol 39 (2) ◽  
pp. 86-87 ◽  
Author(s):  
Shinichi Itsuno ◽  
Devproshad K. Paul ◽  
Mikiya Ishimoto ◽  
Naoki Haraguchi
Keyword(s):  
Quaternary Ammonium ◽  
Alkylation Reaction ◽  
Asymmetric Alkylation ◽  
Polymeric Catalyst

ChemInform Abstract: Designing Chiral Quaternary Ammonium Polymers: Novel Type of Polymeric Catalyst for Asymmetric Alkylation Reaction.

ChemInform ◽  
2010 ◽  
Vol 41 (29) ◽  
pp. no-no
Author(s):  
Shinichi Itsuno ◽  
Devproshad K. Paul ◽  
Mikiya Ishimoto ◽  
Naoki Haraguchi
Keyword(s):  
Quaternary Ammonium ◽  
Alkylation Reaction ◽  
Asymmetric Alkylation ◽  
Polymeric Catalyst

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.

scholarly journals Applications of oxazolidinones as chiral auxiliaries in the asymmetric alkylation reaction applied to total synthesis

RSC Advances ◽  
2016 ◽  
Vol 6 (36) ◽  
pp. 30498-30551 ◽  
Author(s):  
Majid M. Heravi ◽  
Vahideh Zadsirjan ◽  
Behnaz Farajpour
Keyword(s):  
Total Synthesis ◽  
Alkylation Reaction ◽  
Chiral Auxiliaries ◽  
Asymmetric Alkylation

In this review, a number of applications of chiral oxazolidinones in the asymmetric alkylation reaction applied to total synthesis are described.

Oxazolidinone cross-alkylation during Evans’ asymmetric alkylation reaction

Tetrahedron ◽  
2011 ◽  
Vol 67 (47) ◽  
pp. 9104-9111 ◽  
Author(s):  
Nieves Fresno ◽  
Ruth Pérez-Fernández ◽  
Pilar Goya ◽  
Ma Luisa Jimeno ◽  
Ibón Alkorta ◽  
...  
Keyword(s):  
Alkylation Reaction ◽  
Asymmetric Alkylation

Ephedrines as Chiral Auxiliaries in Enantioselective Alkylation Reactions of Acyl Ephedrine Amides and Esters: A Review

2018 ◽  
Vol 15 (1) ◽  
pp. 38-83 ◽  
Author(s):  
Alejandro Cruz ◽  
Itzia I. Padilla-Martínez ◽  
Maria E. Bautista-Ramirez
Keyword(s):  
Asymmetric Synthesis ◽  
Bond Formation ◽  
Alkyl Halides ◽  
Aldol Reactions ◽  
Alkylation Reaction ◽  
Chiral Auxiliaries ◽  
Asymmetric Alkylation ◽  
Chiral Compounds ◽  
High Yields ◽  
Alkylation Reactions

Background: In modern chemistry, the asymmetric synthesis for the preparation of high purity chiral compounds to be used as pharmaceuticals or additives in foods have been of capital importance. Chiral auxiliary reagents are used to control the stereochemistry of the reaction in the generation of new chiral compounds, in this context, Ephedra compounds (ephedrines and pseudoephedrines) and some of their derivatives have been broadly used as chiral ligands in catalysis or chiral inductors in asymmetric synthesis. Objective: This review focuses on recent progress in the use of ephedra compounds and their N-substituted derivatives as chiral auxiliaries in the area of asymmetric synthesis, via the alkylation reaction of the enolates derived from their corresponding N-Acyl or O-Acyl derivatives, in the C-C bond formation. Conclusion: A vast amount of work has been done about the use of ephedra compounds in asymmetric synthesis area, in general, it was found that pseudoephedrines are much more effective than ephedrines and are preferred as chiral auxiliaries in the asymmetric alkylation of the corresponding N-acyl amides or O-Acyl esters. Alkylation with alkyl halides requires the use of more than 4 equivalents of LiCl to accelerate the alkylation rate and to complete the reaction without effecting the diastereoselectivity of the process. In contrast, the use of secondary alkyl halides was found to make the reaction very slow. Furthermore, a lot of work about the alkylation reaction in the opening of epoxides and aziridines, aldolic condensation, Manich reaction, addition of nucleophiles to α,β-unsaturated ephedrine amides and Michael additions have been demonstrated to be effective in the C-C bond formation. The aldol reaction of chiral enolates, proceeds with decreasing yields and enantioselectivities as the steric demand of the α-R of ephedrine amides and the size of carbonyl compound increase. In addition, the use of branched groups on N,N-disubstituted norephedrine esters is highly recommended in the aldol reactions of aromatic and aliphatic aldehydes.In the case of N-Acyl or O-Acyl ephedrines supported on polymers, the reaction proceed with good enantioselectivities but low yields, the enantioselectivities are goods but the yields are low. In general, the removal step of the auxiliary proceeds with low to high yields but without epimerization.

ChemInform Abstract: Asymmetric Alkylation Reaction of α-Fluorotetralone under Phase-Transfer Catalyzed Conditions.

ChemInform ◽  
2010 ◽  
Vol 30 (47) ◽  
pp. no-no
Author(s):  
Shigeru Arai ◽  
Makoto Oku ◽  
Toshimasa Ishida ◽  
Takayuki Shioiri
Keyword(s):  
Phase Transfer ◽  
Alkylation Reaction ◽  
Asymmetric Alkylation

scholarly journals Friedel–Crafts-Type Alkylation of Indoles in Water Using Amphiphilic Resin-Supported 1,10-Phenanthroline–Palladium Complex under Aerobic Conditions

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 193
Author(s):  
Toshimasa Suzuka ◽  
Yuto Ooshiro ◽  
Kazuhito Ogihara
Keyword(s):  
High Selectivity ◽  
Palladium Complex ◽  
Palladium Complexes ◽  
High Yield ◽  
Alkylation Reaction ◽  
Poly Ethylene Glycol ◽  
Aerobic Conditions ◽  
Palladium Catalyzed ◽  
Poly Ethylene ◽  
Polymeric Catalyst

The palladium-catalyzed Friedel-Crafts-type alkylation of indoles in water has been achieved using amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin-supported phenanthroline-palladium complexes in water under aerobic conditions, affording the corresponding products with good-to-high yield. The polymeric catalyst was also found to promote the C3-alkylation reaction to give a thermodynamic alkylation product with high selectivity. The polymeric catalyst was recovered and reused several times without any loss of catalytic activity.

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