Diastereo- and Enantioselective Tandem Michael Addition and Lactonization between Silyl Enolates and α,β-Unsaturated Ketones Catalyzed by a Chiral Quaternary Ammonium Phenoxide

2006 ◽  
Vol 35 (4) ◽  
pp. 360-361 ◽  
Author(s):  
Takashi Tozawa ◽  
Yoshinobu Yamane ◽  
Teruaki Mukaiyama
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Unsaturated Ketones

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.

Highly enantioselective aza-Michael addition reactions of 4-nitrophthalimide with α,β-unsaturated ketones

RSC Advances ◽  
2013 ◽  
Vol 3 (29) ◽  
pp. 11498 ◽  
Author(s):  
Shijun Ma ◽  
Lulu Wu ◽  
Ming Liu ◽  
Xiufang Xu ◽  
Yaodong Huang ◽  
...  
Keyword(s):  
Michael Addition ◽  
Addition Reactions ◽  
Unsaturated Ketones

ChemInform Abstract: Metal Ion-Complexes of α,β-Unsaturated Ketones Acting as Actual Reactive Species in Michael Addition of Ketene Silyl Acetal.

ChemInform ◽  
2010 ◽  
Vol 28 (47) ◽  
pp. no-no
Author(s):  
S. FUKUZUMI ◽  
T. OKAMOTO ◽  
K. YASUI ◽  
T. SUENOBU ◽  
S. ITOH ◽  
...  
Keyword(s):  
Michael Addition ◽  
Metal Ion ◽  
Reactive Species ◽  
Metal Ion Complexes ◽  
Unsaturated Ketones
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