scholarly journals The synthesis of chiral β-naphthyl-β-sulfanyl ketones via enantioselective sulfa-Michael reaction in the presence of a bifunctional cinchona/sulfonamide organocatalyst

2021 ◽  
Vol 17 ◽  
pp. 494-503
Author(s):  
Deniz Tözendemir ◽  
Cihangir Tanyeli
Keyword(s):  
Michael Addition ◽  
Michael Reaction ◽  
Cinchona Alkaloid ◽  
Catalyst Loading ◽  
Asymmetric Transformations ◽  
Chalcone Derivatives ◽  
Mild Conditions ◽  
Michael Adducts

Cinchona alkaloid-derived organocatalysts are widely employed in various asymmetric transformations, yielding products with high enantiopurity. In this respect, a bifunctional quinine-derived sulfonamide organocatalyst was developed to catalyze the asymmetric sulfa-Michael reaction of naphthalene-1-thiol with trans-chalcone derivatives. The target sulfa-Michael adducts were obtained with up to 96% ee under mild conditions and with a low (1 mol %) catalyst loading. Selected enantiomerically enriched sulfa-Michael addition products were subjected to oxidation to obtain the corresponding sulfones.

scholarly journals The Synthesis of Chiral β-Naphthyl-β-Sulfanyl Ketones via Enantioselective Sulfa-Michael Reaction in the Presence of a Bifunctional Cinchona/Sulfonamide Organocatalyst

2020 ◽  
Author(s):  
Deniz Tözendemir ◽  
Cihangir Tanyeli
Keyword(s):  
Michael Reaction ◽  
Cinchona Alkaloid ◽  
Catalyst Loading ◽  
Asymmetric Transformations ◽  
Chalcone Derivatives ◽  
Mild Conditions ◽  
Michael Adducts

Cinchona alkaloid derived organocatalysts are widely employed in various asymmetric transformations, yielding products with high enantiopurity. In this respect, a bifunctional quinine derived sulfonamide organocatalyst was developed to catalyze the asymmetric sulfa-Michael reaction of naphthalene-1-thiol with trans-chalcone derivatives. The target sulfa-Michael adducts were obtained with up to 96% ee under mild conditions and with a low (1 mol%) catalyst loading. Selected enantiomerically enriched SMA products were subjected to oxidation to obtain corresponding sulfones.

Peptidomimetic organocatalysts: efficient Michael addition of ketones onto nitroolefins with very low catalyst loading

RSC Advances ◽  
2014 ◽  
Vol 4 (57) ◽  
pp. 30325-30331 ◽  
Author(s):  
Srivari Chandrasekhar ◽  
Chintakunta Praveen Kumar ◽  
Togapur Pavan Kumar ◽  
Kothapalli Haribabu ◽  
Bharatam Jagadeesh ◽  
...  
Keyword(s):  
Michael Addition ◽  
Michael Reaction ◽  
Catalyst Loading ◽  
Low Catalyst Loading

The syntheses and applications of peptidomimetic triazole-based catalysts are described as efficient organocatalysts in Michael reaction with low loading.

Highly Enantioselective Michael Addition of Dithiomalonates to Nitroolefins Catalyzed by New Bifunctional Chiral Thioureas

Synthesis ◽  
2018 ◽  
Vol 50 (13) ◽  
pp. 2577-2586 ◽  
Author(s):  
Jia-Ni Yuan ◽  
Hui-Xia Liu ◽  
Qin-Qin Tian ◽  
Nan Ji ◽  
Kuo Shen ◽  
...  
Keyword(s):  
Michael Addition ◽  
Mild Conditions ◽  
Highly Efficient ◽  
Michael Adducts ◽  
Asymmetric Michael Addition ◽  
High Yields

We report a highly efficient asymmetric Michael addition of dithiomalonates to trans-β-nitroolefins catalyzed by versatile cinchona-based bifunctional thioureas, which provides the corresponding adducts in high yields (up to 92%) and with excellent enantioselectivities (up to 99% ee) under mild conditions. Replacement of the catalyst with its pseudo-enantiomer gives the Michael adducts with opposite configuration in similar yields and enantioselectivities.

Potassium Hydroxide Catalysed Intermolecular Aza-Michael Addition of 3-Cyanoindole to Aromatic Enones

Synlett ◽  
2017 ◽  
Vol 28 (10) ◽  
pp. 1227-1231 ◽  
Author(s):  
Jingya Yang ◽  
Tianyuan Li ◽  
Hongyan Zhou ◽  
Nana Li ◽  
Dongtai Xie ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
Michael Addition ◽  
Potassium Hydroxide ◽  
Michael Reaction ◽  
Pharmaceutical Compounds ◽  
Catalyst Loading ◽  
Good Substrate ◽  
Substrate Tolerance ◽  
High Yields ◽  
Low Catalyst Loading

Indole is one of the utmost important heterocycles as it is an essential nucleus of many pharmaceutical compounds. Its aza-Michael reaction, however, is underdeveloped because of the moiety’s inherent characteristics. Here, a potassium hydroxide catalysed intermolecular aza-Michael reaction of 3-cyanoindole with aromatic enones is described. A variety of chalcone derivatives are well tolerated and afford the corresponding N-adducts in moderate to high yields. The use of a cheap catalyst, low catalyst loading, mild reaction temperature, and good substrate tolerance make this procedure a direct and facile method for the preparation of N1-functionalized indoles.

N-Heterocyclic Carbene-Catalysed Mukaiyama–Michael Reaction and Mukaiyama Aldol/Mukaiyama–Michael Three-Component Coupling Reaction

2017 ◽  
Vol 70 (4) ◽  
pp. 436 ◽  
Author(s):  
Kim Nguyen ◽  
David W. Lupton
Keyword(s):  
Michael Addition ◽  
Michael Reaction ◽  
Coupling Reaction ◽  
Enol Ethers ◽  
Chalcone Derivatives ◽  
Mukaiyama Aldol ◽  
Related Reaction ◽  
Three Component Coupling

An N-heterocyclic carbene-catalysed Mukaiyama–Michael addition between several trimethylsilyl (TMS) enol ethers and chalcone derivatives has been discovered. In addition, a related reaction cascade involving dehydrative Mukaiyama aldol followed by a Mukaiyama–Michael addition process has been developed. The later reaction can also be achieved as a three-component coupling reaction. The enantioselective variant of these reactions has been examined with homochiral catalysts. Though these catalysts were active, they fail to achieve enantioinduction.

scholarly journals Novel Selenoureas Based on Cinchona Alkaloid Skeleton: Synthesis and Catalytic Investigations

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 600
Author(s):  
Mariola Zielińska-Błajet ◽  
Joanna Najdek
Keyword(s):  
Michael Addition ◽  
Catalytic Performance ◽  
Cinchona Alkaloid ◽  
Addition Reactions ◽  
Efficient Approach ◽  
Mild Conditions ◽  
Asymmetric Michael Addition

An efficient approach to the synthesis of chiral selenoureas consisting of Cinchona alkaloid scaffolds was described. The new selenoureas were assessed as bifunctional organocatalysts in the asymmetric Michael addition reactions under mild conditions. The best results were obtained for selenoureas bearing the 4-fluorophenyl group. These catalysts promoted the reactions with enantioselectivities of up to 96% ee. Additionally, the catalytic performance of the thiourea and selenourea counterpart was compared.

One-pot synthesis of β-lactams by the Ugi and Michael addition cascade reaction

2018 ◽  
Vol 16 (33) ◽  
pp. 6096-6105 ◽  
Author(s):  
Xing Gao ◽  
Chunhui Shan ◽  
Zhihao Chen ◽  
Yan Liu ◽  
Xia Zhao ◽  
...  
Keyword(s):  
Michael Addition ◽  
Michael Reaction ◽  
Cascade Reaction ◽  
One Pot ◽  
Diversity Oriented Synthesis ◽  
Mild Conditions ◽  
One Pot Synthesis ◽  
Reaction Cascades

A diversity-oriented synthesis of β-lactams via Ugi/Michael reaction cascades under mild conditions was achieved.

Enantioselective N-Alkylation of Nitroindoles under Phase-Transfer Catalysis

Synthesis ◽  
2019 ◽  
Vol 52 (07) ◽  
pp. 1047-1059 ◽  
Author(s):  
Dmitri Trubitsõn ◽  
Jevgenija Martõnova ◽  
Kristin Erkman ◽  
Andrus Metsala ◽  
Jaan Saame ◽  
...  
Keyword(s):  
Phase Transfer Catalysis ◽  
Michael Reaction ◽  
Phase Transfer ◽  
Spectrophotometric Titration ◽  
Cinchona Alkaloid ◽  
Indole Ring ◽  
Phase Transfer Catalysts ◽  
Michael Adducts ◽  
Michael Acceptors ◽  
High Yields

An asymmetric phase-transfer-catalyzed N-alkylation of substituted indoles with various Michael acceptors was studied. Acidities of nitroindoles were determined in acetonitrile by UV-Vis spectrophotometric titration. There was essentially no correlation between acidity and reactivity in the aza-Michael reaction. The position of the nitro group on the indole ring was essential to control the stereoselectivity of the reaction. Michael adducts were obtained in high yields and moderate enantioselectivities in the reaction between 4-nitroindole and various Michael acceptors in the presence of cinchona alkaloid based phase-transfer catalysts. In addition to outlining the scope and limitations of the method, the geometries of the transition states of the reaction were calculated.

scholarly journals Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

2019 ◽  
Vol 15 ◽  
pp. 1289-1297 ◽  
Author(s):  
Alexander N Reznikov ◽  
Anastasiya E Sibiryakova ◽  
Marat R Baimuratov ◽  
Eugene V Golovin ◽  
Victor B Rybakov ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Bioactive Compounds ◽  
Michael Addition ◽  
Michael Reaction ◽  
High Yield ◽  
Michael Adducts ◽  
Significant Rate ◽  
Asymmetric Michael Addition ◽  
Stereogenic Centers ◽  
Asymmetric Michael Reaction

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.

scholarly journals Enantioselective cyanation via radical-mediated C–C single bond cleavage for synthesis of chiral dinitriles

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Tao Wang ◽  
Yi-Ning Wang ◽  
Rui Wang ◽  
Bo-Chao Zhang ◽  
Chi Yang ◽  
...  
Keyword(s):  
Ring Opening ◽  
Bond Cleavage ◽  
Catalyst Loading ◽  
Small Ring ◽  
Single Bond ◽  
Asymmetric Transformations ◽  
Mild Conditions ◽  
Ring Opening Reaction ◽  
High Yields ◽  
Low Catalyst Loading

AbstractRing-opening reaction via selective cleavage of C–C bond is known as a powerful strategy for construction of complex molecules. Complementary to the ionic process focusing on mostly small ring systems, radical-mediated C–C bond cleavage offers a solution for further diverse enantioselective functionalization benefited from its mild conditions, whereas such asymmetric transformations are still limited to three-membered rings so far. Herein, we describe radical-mediated ring-opening and enantioselective cyanation of four- and five-membered cycloketone oxime esters to access chiral 1,5- and 1,6-dinitriles. Employment of dual photoredox/copper catalysis is essential for the asymmetric ring-opening cyanation of cyclopentanone oxime esters. Both reactions proceed under mild conditions giving chiral dinitriles in high yields and enantioselectivity with low catalyst loading and broad substrate scope. The products dinitriles can be converted to valuable optically active diamides and diamines. Mechanistic studies indicate that the benzylic radical generated via C–C single bond cleavage is involved in the catalytic cycle.

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