Efficient Synthesis of Substituted 3-Amino-3,4-dihydropyran-2-ones Diastereo and Enantioselective Tandem Michael Addition and Lactonization between α,β-Unsaturated Ketones and Glycine-Derived Silyl Enolates Using a Chiral Quaternary Ammonium Phenoxide

Heterocycles ◽  
2007 ◽  
Vol 72 (1) ◽  
pp. 553 ◽  
Author(s):  
Teruaki Mukaiyama ◽  
Hitoshi Nagao ◽  
Yoshinobu Yamane
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Efficient Synthesis ◽  
Unsaturated Ketones

Enantioselective cascade double Michael addition of 3-nitro-2H-chromenes and acyclic enones: efficient synthesis of functionalized tricyclic chroman derivatives

2015 ◽  
Vol 13 (37) ◽  
pp. 9600-9609 ◽  
Author(s):  
Jun-Hua Li ◽  
Da-Ming Du
Keyword(s):  
Michael Addition ◽  
Primary Amine ◽  
Efficient Synthesis ◽  
Unsaturated Ketones

An efficient protocol for the construction of enantiomerically enriched tetrahydro-6H-benzo[c]chromenes by the cascade double Michael addition of 3-nitro-2H-chromenes and α,β-unsaturated ketones catalyzed by a quinine-derived primary amine has been developed.

scholarly journals A Versatile Method for Preparing Polysaccharide Conjugates via Thiol-Michael Addition

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1905
Author(s):  
Junyi Chen ◽  
Xutao Ma ◽  
Kevin J. Edgar
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Synthetic Approach ◽  
Renewable Materials ◽  
Fast Reaction ◽  
Michael Additions ◽  
Antimicrobial Performance ◽  
A Charge ◽  
Post Modification ◽  
Fast Reaction Rate

Polysaccharide conjugates are important renewable materials. If properly designed, they may for example be able to carry drugs, be proactive (e.g., with amino acid substituents) and can carry a charge. These aspects can be particularly useful for biomedical applications. Herein, we report a simple approach to preparing polysaccharide conjugates. Thiol-Michael additions can be mild, modular, and efficient, making them useful tools for post-modification and the tailoring of polysaccharide architecture. In this study, hydroxypropyl cellulose (HPC) and dextran (Dex) were modified by methacrylation. The resulting polysaccharide, bearing α,β-unsaturated esters with tunable DS (methacrylate), was reacted with various thiols, including 2-thioethylamine, cysteine, and thiol functional quaternary ammonium salt through thiol-Michael addition, affording functionalized conjugates. This click-like synthetic approach provided several advantages including a fast reaction rate, high conversion, and the use of water as a solvent. Among these polysaccharide conjugates, the ones bearing quaternary ammonium salts exhibited competitive antimicrobial performance, as supported by a minimum inhibitory concentration (MIC) study and tracked by SEM characterization. Overall, this methodology provides a versatile route to polysaccharide conjugates with diverse functionalities, enabling applications such as antimicrobial activity, gene or drug delivery, and biomimicry.

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