Organocatalytic asymmetric Michael addition of 1-acetylcyclohexene and 1-acetylcyclopentene to nitroolefins

2015 ◽  
Vol 13 (25) ◽  
pp. 7076-7083 ◽  
Author(s):  
Utpal Nath ◽  
Ankush Banerjee ◽  
Bidhan Ghosh ◽  
Subhas Chandra Pan

The first organocatalytic asymmetric Michael reaction between α-branched enones namely 1-acetylcyclohexene, 1-acetylcyclopentene and 1-acetylcyclobutene with nitroolefins has been developed using primary amines as catalysts.

2020 ◽  
Vol 7 (11) ◽  
pp. 1343-1348
Author(s):  
Luyao Li ◽  
Bo Zhu ◽  
Huihui Fan ◽  
Zhiyong Jiang ◽  
Junbiao Chang

Herein, we report a chiral bifunctional thiourea catalyzed asymmetric Michael addition reaction between 2-(trifluoromethyl)oxazol-5(2H)-one as a direct C-2-position nucleophile to 4-nitro-5-styrylisoxazoles for the first time.


2019 ◽  
Vol 15 ◽  
pp. 1289-1297 ◽  
Author(s):  
Alexander N Reznikov ◽  
Anastasiya E Sibiryakova ◽  
Marat R Baimuratov ◽  
Eugene V Golovin ◽  
Victor B Rybakov ◽  
...  

Functionally substituted sulfones with stereogenic centers are valuable reagents in organic synthesis and key motifs in some bioactive compounds. The asymmetric Michael addition of β-ketosulfones to conjugated nitroalkenes in the presence of Ni(II) complexes with various chiral vicinal diamines was studied. This reaction provides convenient access to non-racemic 4-nitro-2-sulfonylbutan-1-ones with two stereocenters with high yield and excellent enantioselectivity (up to 99%). It has been established that the catalytic Michael reaction itself was carried out with high diastereoselectivity, but the Michael adducts may epimerize at the C-2 position at a significant rate. Conditions for the preparation of individual diastereomers were found.


2004 ◽  
Vol 59 (4) ◽  
pp. 375-379 ◽  
Author(s):  
Jens Christoffers ◽  
Wolfgang Frey ◽  
Heiko Scharl ◽  
Angelika Baro

AbstractEnantiopure Boc-protected piperidine derivative (+)-5c, with a quaternary stereocenter, was obtained by copper-catalyzed, L-valine diethylamide-mediated Michael reaction. For determination of the absolute configuration, 5c was derivatized by cyclization with pyrrolidine/AcOH to give compound 6 with bicyclo[4.4.0]-constitution, deprotection of the amino function with TFA and subsequent reaction with 2-iodobenzoic acid to yield the crystalline bicyclic amide 7. X-ray crystallographic analysis confirmed the constitution of compounds 5c and 6 and established the (R) configuration of 7. Thus, starting Michael addition product (+)-5c has to be (S) configured, because an epimerization at the quaternary stereocenter is excluded. This result is in accordance with our working model of the Cu-catalyzed, auxiliary-assisted Michael reaction.


ChemInform ◽  
2010 ◽  
Vol 41 (48) ◽  
pp. no-no
Author(s):  
Santos Fustero ◽  
Silvia Catalan ◽  
Maria Sanchez-Rosello ◽  
Antonio Simon-Fuentes ◽  
Carlos del Pozo

2010 ◽  
Vol 12 (15) ◽  
pp. 3484-3487 ◽  
Author(s):  
Santos Fustero ◽  
Silvia Catalán ◽  
María Sánchez-Roselló ◽  
Antonio Simón-Fuentes ◽  
Carlos del Pozo

RSC Advances ◽  
2015 ◽  
Vol 5 (115) ◽  
pp. 95079-95086 ◽  
Author(s):  
Eszter Varga ◽  
László Tamás Mika ◽  
Antal Csámpai ◽  
Tamás Holczbauer ◽  
György Kardos ◽  
...  

The mechanism of cinchona–squaramide organocatalytic Michael addition was studied usingin situIR and NMR experiments. As a result, not only kinetic parameters were determined but a stereoselective retro-Michael reaction was also observed.


Synthesis ◽  
2021 ◽  
Author(s):  
Azim Ziyaei Halimehjani ◽  
Petr Beier ◽  
Maryam Khalili Foumeshi ◽  
Ali Alaei ◽  
Blanka Klepetářová

AbstractThiazolidine-2-thiones were prepared via a novel multicomponent reaction of primary amines (amino acids), carbon disulfide, and γ-bromocrotonates. The reaction proceeds via a domino alkylation/intramolecular Michael addition to provide the corresponding thiazolidine-2-thiones in high to excellent yields. By using diamines in this protocol, bis(thiazolidine-2-thiones) derivatives were synthesized. The synthetic utility of the adducts was demonstrated by hydrolysis, amidation, and oxidation reactions.


2010 ◽  
Vol 16 (23) ◽  
pp. 7030-7038 ◽  
Author(s):  
Ying-Fang Ting ◽  
Chihliang Chang ◽  
Raju Jannapu Reddy ◽  
Dhananjay R. Magar ◽  
Kwunmin Chen

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