Synthesis of Cinchona Alkaloid Derived Chiral Squaramide Polymers by ADMET Polymerization and Their Application to Asymmetric Catalysis

2018 ◽  
Vol 47 (9) ◽  
pp. 1220-1223 ◽  
Author(s):  
Mohammad Shahid Ullah ◽  
Shinichi Itsuno
Keyword(s):  
Asymmetric Catalysis ◽  
Cinchona Alkaloid ◽  
Admet Polymerization

scholarly journals ADMET Polymerization of Dimeric Cinchona Squaramides for the Preparation of a Highly Enantioselective Polymeric Organocatalyst

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 591
Author(s):  
Mohammad Shahid Ullah ◽  
Sadia Afrin Chhanda ◽  
Shinichi Itsuno
Keyword(s):  
Second Generation ◽  
Michael Reaction ◽  
Cinchona Alkaloids ◽  
Cinchona Alkaloid ◽  
Acyclic Diene Metathesis ◽  
Chiral Polymers ◽  
Admet Polymerization ◽  
Reaction Condition ◽  
High Yields ◽  
Asymmetric Michael Reaction

Under the acyclic diene metathesis (ADMET) reaction condition, the C3-vinyl groups of cinchona alkaloids readily react with each other to form a C-C bond. A novel type of cinchona alkaloid polymers was synthesized from dimeric cinchona squaramides using the Hoveyda-Grubbs’ second-generation catalysts (HG2) by means of ADMET reaction. The chiral polymers, containing cinchona squaramide moieties in their main chains, were subsequently employed as catalysts for the enantioselective Michael reaction to give the corresponding chiral adducts in high yields with excellent enantioselectivity and diastereoselectivity. Both enantiomers from the asymmetric Michael reaction were distinctively prepared while using the polymeric catalysts, possessing pseudoenantiomeric structures. The catalysts were readily recovered from the reaction mixture and recycled several times due to the insolubility of the cinchona-based squaramide polymers.

The Use of cinchona Alkaloid Derivatives as Chiral Ligands and Organocatalysts in Asymmetric Catalysis

2021 ◽  
Vol 18 ◽  
Author(s):  
Minghua Li ◽  
Wei He ◽  
Sheng-Yong Zhang
Keyword(s):  
Asymmetric Catalysis ◽  
Organic Synthesis ◽  
Cinchona Alkaloids ◽  
Cinchona Alkaloid ◽  
Chiral Induction ◽  
Design And Synthesis ◽  
The Past ◽  
Oxidation Reduction ◽  
Induction Process ◽  
New Ideas

: Cinchona alkaloids are natural products extracted from cinchona plants, which contain quinine, quinidine, cinchonine, and cinchonidine. During the past 30 years, due to their attractive structural properties, these compounds have been used as chiral skeletons and organocatalysts in asymmetric organic synthesis. In this review, we summarize the applications of cinchona alkaloids derivatives in asymmetric catalysis recently developed by our group, including oxidation, reduction, and C-C bonds formation. These studies solved some of the problems with the various asymmetric reactions discussed, while also enriching alkaloids chemistry, providing new ideas for the design and synthesis of chiral catalysts, and providing abundant experimental data for the chiral induction process.

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