scholarly journals Substrate-Controlled Michael Additions of Titanium Enolates from Chiral α-Benzyloxy Ketones to Conjugated Nitroalkenes

2017 ◽  
Vol 2017 (38) ◽  
pp. 5776-5784 ◽  
Author(s):  
Alejandro Gómez-Palomino ◽  
Adrián Barrio ◽  
Pedro García-Lorente ◽  
Pedro Romea ◽  
Fèlix Urpí ◽  
...  
Keyword(s):  
Michael Additions ◽  
Titanium Enolates

Enantioselective Michael Addition of Malonates to Enones

2020 ◽  
Vol 24 (7) ◽  
pp. 746-773
Author(s):  
Péter Bakó ◽  
Tamás Nemcsok ◽  
Zsolt Rapi ◽  
György Keglevich
Keyword(s):  
Michael Addition ◽  
Activity Relationship ◽  
Chalcone Derivatives ◽  
Michael Additions ◽  
Michael Reactions ◽  
Structure Activity ◽  
Cyclic Enones ◽  
Michael Acceptors ◽  
Relationship Of ◽  
Enantioselective Catalysts

: Many catalysts were tested in asymmetric Michael additions in order to synthesize enantioenriched products. One of the most common reaction types among the Michael reactions is the conjugated addition of malonates to enones making it possible to investigate the structure–activity relationship of the catalysts. The most commonly used Michael acceptors are chalcone, substituted chalcones, chalcone derivatives, cyclic enones, while typical donors may be dimethyl, diethyl, dipropyl, diisopropyl, dibutyl, di-tert-butyl and dibenzyl malonates. This review summarizes the most important enantioselective catalysts applied in these types of 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.

Chemoselective Double Michael Addition: Synthesis of 2,6-Diarylspiro[Cyclohexane-1,3′-Indoline]-2′,4-Diones via Addition of Indolin-2-One to Divinyl Ketones

2017 ◽  
Vol 41 (3) ◽  
pp. 168-171 ◽  
Author(s):  
Zheng Li ◽  
Jiasheng Li ◽  
Jingya Yang
Keyword(s):  
Michael Addition ◽  
High Yield ◽  
Reaction Conditions ◽  
Michael Additions

Seventeen examples of 2,6-diarylspiro[cyclohexane-1,3′-indoline]-2′4-diones were efficiently prepared by the Cs2CO3-catalysed chemoselective double Michael additions of indolin-2-one to divinyl ketones. This method has the advantage of high chemoselectivity, mild reaction conditions, high yield and atom- and step-economy.

scholarly journals α,β-Unsaturated acyl ammonium species as reactive intermediates in organocatalysis: an update

2020 ◽  
Author(s):  
Jacqueline Bitai ◽  
Matthew Westwood ◽  
Andrew D Smith
Keyword(s):  
Reactive Intermediates ◽  
Domino Reactions ◽  
Michael Additions ◽  
Unsaturated Acyl

α,β-Unsaturated acyl ammonium species are versatile intermediates that have been applied in a variety of transformation including Michael additions, domino reactions and cycloadditions. Many of these transformations are promoted by...

ChemInform Abstract: Generation and Trapping of 5,6-Dimethylenepyrimidin-4-ones in Diels- Alder and Michael Additions.

ChemInform ◽  
2010 ◽  
Vol 27 (20) ◽  
pp. no-no
Author(s):  
A. C. TOME ◽  
J. A. S. CAVALEIRO ◽  
R. C. STORR
Keyword(s):  
Diels Alder ◽  
Michael Additions

ChemInform Abstract: Reactivity of Trifluoromethyl Enones in Michael Additions.

ChemInform ◽  
2010 ◽  
Vol 26 (23) ◽  
pp. no-no
Author(s):  
R. ARNAUD ◽  
A. BENSADAT ◽  
A. GHOBSI ◽  
A. LAURENT ◽  
I. LE DREAN ◽  
...  
Keyword(s):  
Michael Additions

Enzyme Mimics for Michael Additions with Novel Proton Transport Groups

2008 ◽  
Vol 2008 (14) ◽  
pp. 2397-2403 ◽  
Author(s):  
Luis Simón ◽  
Francisco M. Muñiz ◽  
Silvia Sáez ◽  
César Raposo ◽  
Joaquín R. Morán
Keyword(s):  
Proton Transport ◽  
Enzyme Mimics ◽  
Michael Additions

ChemInform Abstract: 4-Aminothioureaprolinal Dithioacetal as a Catalyst for Highly Enantioselective Michael Additions of Ketones and Aldehydes to Nitroolefins.

ChemInform ◽  
2011 ◽  
Vol 42 (18) ◽  
pp. no-no
Author(s):  
Yong-Ming Chuan ◽  
Li-Yang Yin ◽  
Yan-Mei Zhang ◽  
Yun-Gui Peng
Keyword(s):  
Michael Additions
Sign in / Sign up

Export Citation Format

Share Document