Bifunctional phase-transfer catalysts for fixation of CO2 with epoxides under ambient pressure

2019 ◽  
Vol 21 (19) ◽  
pp. 5231-5237 ◽  
Author(s):  
Yue-Dan Li ◽  
Dong-Xiao Cui ◽  
Jun-Chao Zhu ◽  
Ping Huang ◽  
Zhuang Tian ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Phase Transfer ◽  
Ambient Pressure ◽  
Cyclic Carbonates ◽  
Donor Group ◽  
Phase Transfer Catalysts ◽  
Mild Conditions

A series of bifunctional phase-transfer catalysts with a quaternary onium center and a hydrogen-bonding donor group were prepared for the fixation of CO2 with epoxides under mild conditions by using a CO2 balloon (1 atm) to produce cyclic carbonates up to 95% yields.

Organocatalyzed Heterocyclic Transformations In Green Media: A Review

2020 ◽  
Vol 07 ◽  
Author(s):  
Neslihan Demirbas ◽  
Ahmet Demirbas
Keyword(s):  
Hydrogen Bonding ◽  
Phase Transfer ◽  
Noncovalent Interactions ◽  
Binding Capacity ◽  
Chemical Transformations ◽  
Organic Transformations ◽  
Phase Transfer Catalysts ◽  
Waste Production ◽  
Synthetic Methodologies ◽  
Organocatalytic Reactions

Background: Since the discovery of metal-free catalysts or organocatalysts about twenty years ago, a number of small molecules with different structures have been using to accelerate organic transformations. With the development of environmental awareness, in order to obtain highly privileged scaffolds, scientists have directed their studies towards the synthetic methodologies which minimize or preferably eliminate the formation of waste, avoid from toxic solvents and reagents and use renewable starting materials as far as possible. Methods: In this connection, the organocatalytic reactions providing efficiency and selectivity for most of case have become an endless topic in organic chemistry since several advantages from both practical and environmental standpoints. Organocatalysts supplying transformation of reactants into products with the least possible waste production have been serving to the concept of green chemistry. Results and Conclusion: Organocatalysts have been classified on the basis of their binding capacity to the substrate with covalently or noncovalent interactions involving hydrogen bonding and electrostatic interaction. Diverse types of small organic compounds including proline and its derivatives, phase-transfer catalysts, (thio)urease, phosphoric acids, sulfones, N-oxides, guanidines, cinchona derivatives, aminoindanol and amino acids have been utilized as hydrogen bonding organocatalysts in different chemical transformations.

Aromatic guanidines as highly active binary catalytic systems for the fixation of CO2 into cyclic carbonates under mild conditions

2019 ◽  
Vol 9 (15) ◽  
pp. 3879-3886 ◽  
Author(s):  
Ángela Mesías-Salazar ◽  
Javier Martínez ◽  
René S. Rojas ◽  
Fernando Carrillo-Hermosilla ◽  
Alberto Ramos ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Reaction Temperature ◽  
Cyclic Carbonates ◽  
Considerable Decrease ◽  
Catalytic Systems ◽  
Mild Conditions ◽  
Highly Active

The formation of hydrogen bonding causes a considerable decrease in the reaction temperature and CO2 pressure used in this process.

scholarly journals The Synthesis of Hydrobenzoin-Based Monoaza Crown Ethers and Their Application as Recyclable Enantioselective Catalysts

2019 ◽  
Vol 150 (4) ◽  
pp. 930-938 ◽  
Author(s):  
Tamás Nemcsok ◽  
Zsolt Rapi ◽  
Péter Bagi ◽  
Attila Oláh ◽  
György Keglevich ◽  
...  
Keyword(s):  
Crown Ethers ◽  
Phase Transfer ◽  
Asymmetric Reactions ◽  
Asymmetric Epoxidation ◽  
Salt Formation ◽  
Lariat Ethers ◽  
Chalcone Derivatives ◽  
Phase Transfer Catalysts ◽  
Mild Conditions ◽  
Enantioselective Catalysts

Abstract New recyclable monoaza-15-crown ethers have been synthesized starting from (R,R)-(+)- and (S,S)-(−)-hydrobenzoin. These macrocycles proved to be efficient and reusable phase transfer catalysts in a few asymmetric reactions under mild conditions. The asymmetric epoxidation of trans-chalcone took place with up to 81% ee, while using other chalcone derivatives, the products were formed with 68–88% ee. The hydrobenzoin-based lariat ethers were also tested in the cyclopropanation of a few electron deficient olefins using diethyl bromomalonate to afford the product with good enantioselectivities (54–75% ee). The catalysts were recovered by salt formation, followed by extraction, and were reused without the loss of the activity and effect on the enantioselectivity. Graphic Abstract The synthesis of hydrobenzoin-based monaza crown ethers and their application as recyclable enantioselective catalysts.

Green Application of Phase-Transfer Catalysis in Oxidation: A Comprehensive Review

2020 ◽  
Vol 17 (4) ◽  
pp. 405-411
Author(s):  
Chuan-Hui Wang ◽  
Chen-Fu Liu ◽  
Guo-Wu Rao
Keyword(s):  
Organic Chemistry ◽  
Green Chemistry ◽  
Oxidation Reaction ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Important Application ◽  
Oxidation Reactions ◽  
Comprehensive Review ◽  
Phase Transfer Catalysts ◽  
Onium Salts

Oxidation reactions have emerged as one of the most versatile tools in organic chemistry. Various onium salts such as ammonium, phosphonium, arsonium, bismuthonium, tellurium have been used as phase transfer catalysts in many oxidation reactions. Certainly, considerable catalysts have been widely used in Phase-Transfer Catalysis (PTC). This review focuses on the application of PTC in various oxidation reaction. Furthermore, PTC also conforms to the concept of “Green Chemistry”. <p></p> • Oxidation has become one of the most widely used tools in organic chemistry and phase transfer catalysts has been widely used in oxidation. <p></p> • The application of phase transfer catalysts in oxidation reaction will be summarized. <p></p> • Phase transfer catalysts have important application in various oxidation reaction.

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