Asymmetric Epoxidation Catalyzed by Novel Azacrown Ether-Type Chiral Quaternary Ammonium Salts under Phase-Transfer Catalytic Conditions.

ChemInform ◽  
2006 ◽  
Vol 37 (33) ◽  
Author(s):  
Kazushige Hori ◽  
Mina Tamura ◽  
Keita Tani ◽  
Nagatoshi Nishiwaki ◽  
Masahiro Ariga ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Phase Transfer ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Asymmetric Epoxidation ◽  
Azacrown Ether

Asymmetric epoxidation catalyzed by novel azacrown ether-type chiral quaternary ammonium salts under phase-transfer catalytic conditions

2006 ◽  
Vol 47 (18) ◽  
pp. 3115-3118 ◽  
Author(s):  
Kazushige Hori ◽  
Mina Tamura ◽  
Keita Tani ◽  
Nagatoshi Nishiwaki ◽  
Masahiro Ariga ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Phase Transfer ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Asymmetric Epoxidation ◽  
Azacrown Ether

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.

Esterification of 1,4-dichlorobutane with sodium formate under solid–liquid phase transfer catalysis. A kinetic study

1989 ◽  
Vol 67 (2) ◽  
pp. 245-249 ◽  
Author(s):  
Hayder A. Zahalka ◽  
Yoel Sasson
Keyword(s):  
Liquid Phase ◽  
Kinetic Study ◽  
Quaternary Ammonium ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Sodium Formate ◽  
Product Distribution ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Solid Liquid

Kinetic data are reported regarding the esterification of 1,4-dichlorobutane with sodium formate catalyzed by quaternary ammonium salts as a model for reactions in series, under solid–liquid phase transfer conditions. The process was found to follow a consecutive first-order mechanism of the general type A → R → S. The reactivity of the quaternary ammonium salts with regard to the counteranion was Cl− > Br− > 1− > HSO4−. The reaction rate was linearly dependent on catalyst concentration up to 12 mol% of catalyst relative to the substrate. Above this concentration the rate was constant and independent of the amount of the catalyst. The activation energy of the two consecutive steps was found to be similar (21 kcal/mol). Therefore, the product distribution (R/S) is not appreciably affected by temperature. A mechanism termed "Thin aqueous boundary layer" is suggested for nucleophilic displacement reactions under solid–liquid phase transfer conditions. Keywords: phase transfer catalysis, series reactions, kinetic study.

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