Organocatalytic Asymmetric Sulfa-Michael/Michael Addition Reactions: A Strategy for the Synthesis of Highly Substituted Chromans with a Quaternary Stereocenter

2010 ◽  
Vol 122 (45) ◽  
pp. 8557-8561 ◽  
Author(s):  
Xu-Fan Wang ◽  
Qiu-Lin Hua ◽  
Ying Cheng ◽  
Xiao-Lei An ◽  
Qing-Qing Yang ◽  
...  
Keyword(s):  
Michael Addition ◽  
Addition Reactions ◽  
Quaternary Stereocenter

Thia-Michael Addition Reactions in Water Using 3-[Bis(Alkylthio) Methylene] Pentane-2,4-Diones as Odorless and Efficient Thiol Equivalents

2007 ◽  
Vol 4 (4) ◽  
pp. 281-284 ◽  
Author(s):  
Yanyan Chai ◽  
Dewen Dong ◽  
Yan Ouyang ◽  
Yongjiu Liang ◽  
Yan Wang ◽  
...  
Keyword(s):  
Michael Addition ◽  
Addition Reactions

scholarly journals Recoverable Phospha-Michael Additions Catalyzed by a 4-N,N-Dimethylaminopyridinium Saccharinate Salt or a Fluorous Long-Chained Pyridine: Two Types of Reusable Base Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1159
Author(s):  
Eskedar Tessema ◽  
Vijayanath Elakkat ◽  
Chiao-Fan Chiu ◽  
Jing-Hung Zheng ◽  
Ka Long Chan ◽  
...  
Keyword(s):  
Michael Addition ◽  
Polar Solvent ◽  
Addition Reaction ◽  
High Yield ◽  
Addition Reactions ◽  
Polar Solvents ◽  
Unsaturated Bond ◽  
Base Catalysts ◽  
Michael Additions

Phospha-Michael addition, which is the addition reaction of a phosphorus-based nucleophile to an acceptor-substituted unsaturated bond, certainly represents one of the most versatile and powerful tools for the formation of P-C bonds, since many different electrophiles and P nucleophiles can be combined with each other. This offers the possibility to access many diversely functionalized products. In this work, two kinds of basic pyridine-based organo-catalysts were used to efficiently catalyze phospha-Michael addition reactions, the 4-N,N-dimethylaminopyridinium saccharinate (DMAP·Hsac) salt and a fluorous long-chained pyridine (4-Rf-CH2OCH2-py, where Rf = C11F23). These catalysts have been synthesized and characterized by Lu’s group. The phospha-Michael addition of diisopropyl, dimethyl or triethyl phosphites to α, β-unsaturated malonates in the presence of those catalysts showed very good reactivity with high yield at 80–100 °C in 1–4.5 h with high catalytic recovery and reusability. With regard to significant catalytic recovery, sometimes more than eight cycles were observed for DMAP·Hsac adduct by using non-polar solvents (e.g., ether) to precipitate out the catalyst. In the case of the fluorous long-chained pyridine, the thermomorphic method was used to efficiently recover the catalyst for eight cycles in all the reactions. Thus, the easy separation of the catalysts from the products revealed the outstanding efficacy of our systems. To our knowledge, these are good examples of the application of recoverable organo-catalysts to the DMAP·Hsac adduct by using non-polar solvent and a fluorous long-chained pyridine under the thermomorphic mode in phospha-Michael addition reactions.

Highly Stereoselective Michael Addition Reactions of CamTHP*-Desymmetrized Glycinamide for the Synthesis of Functionally Dense Amino Acid Derivatives

2004 ◽  
Vol 6 (24) ◽  
pp. 4427-4429 ◽  
Author(s):  
Darren J. Dixon ◽  
Richard A. J. Horan ◽  
Nathaniel J. T. Monck ◽  
Paul Berg
Keyword(s):  
Amino Acid ◽  
Michael Addition ◽  
Amino Acid Derivatives ◽  
Addition Reactions

The first peripherally masked thiol dendrimers: a facile and highly efficient functionalization strategy of polyester dendrimers via one-pot xanthate deprotection/thiol–acrylate Michael addition reactions

2014 ◽  
Vol 50 (50) ◽  
pp. 6574-6577 ◽  
Author(s):  
Sam E. R. Auty ◽  
Oliver Andrén ◽  
Michael Malkoch ◽  
Steven P. Rannard
Keyword(s):  
Michael Addition ◽  
Addition Reactions ◽  
One Pot ◽  
Highly Efficient

We present the first xanthate surface functional dendrimers which undergo rapid one-pot deprotection to thiols and subsequent acrylate Michael addition .

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