scholarly journals Recent Advances in Selected Asymmetric Reactions Promoted by Chiral Catalysts: Cyclopropanations, Friedel–Crafts, Mannich, Michael and Other Zinc-Mediated Processes—An Update

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1762
Author(s):  
Michał Rachwalski ◽  
Aleksandra Buchcic-Szychowska ◽  
Stanisław Leśniak
Keyword(s):  
Michael Reaction ◽  
Review Article ◽  
Asymmetric Reactions ◽  
Zinc Ions ◽  
Chiral Catalyst ◽  
Asymmetric Transformations ◽  
Asymmetric Cyclopropanation ◽  
Chiral Systems ◽  
Optically Pure ◽  
Synthesis Reactions

The main purpose of this review article is to present selected asymmetric synthesis reactions in which chemical and stereochemical outcomes are dependent on the use of an appropriate chiral catalyst. Optically pure or enantiomerically enriched products of such transformations may find further applications in various fields. Among an extremely wide variety of asymmetric reactions catalyzed by chiral systems, we are interested in: asymmetric cyclopropanation, Friedel–Crafts reaction, Mannich and Michael reaction, and other stereoselective processes conducted in the presence of zinc ions. This paper describes the achievements of the above-mentioned asymmetric transformations in the last three years. The choice of reactions is related to the research that has been carried out in our laboratory for many years.

Preparation of Optically Pure Dinuclear Cobalt(III) Complex with Λ-Configuration as a Dianionic Chiral Catalyst

Heterocycles ◽  
2021 ◽  
Vol 103 (1) ◽  
pp. 225
Author(s):  
Shinobu Takizawa ◽  
Hiroaki Sasai ◽  
Mohamed S. H. Salem ◽  
Ankit Kumar ◽  
Makoto Sako ◽  
...  
Keyword(s):  
Chiral Catalyst ◽  
Optically Pure

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 Proline Based Chiral Ionic Liquids for Enantioselective Michael Reaction

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Kaoru Nobuoka ◽  
Satoshi Kitaoka ◽  
Tsutomu Kojima ◽  
Yuuki Kawano ◽  
Kazuya Hirano ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Catalytic Activity ◽  
Ionic Liquids ◽  
Positive Charge ◽  
Michael Reaction ◽  
Chiral Synthesis ◽  
Chiral Catalyst ◽  
New Approach ◽  
Chiral Ionic Liquids ◽  
Chiral Ionic Liquid

Chiral ionic liquids, starting from (S)-proline, have been prepared and evaluated the ability of a chiral catalyst. In Michael reaction of trans-β-nitrostyrene and cyclohexanone, all the reactions were carried out under homogeneous conditions without any solvent except for excess cyclohexanone. The chiral ionic liquid catalyst with the positive charge delocalized bulky pyrrolidinium cation shows excellent yields (up to 92%), diastereoselectivities (syn/anti = 96/4), and enantioselectivities (up to 95% ee) and could be reused at least three times without any loss of its catalytic activity. Such results demonstrated a promising new approach for green and economic chiral synthesis by using the chiral ionic liquids as a chiral catalyst and a chiral medium.

scholarly journals Synthesis of 2-Amino-apopinan-3-ol and Applications of Its Derivatives in Asymmetric Reduction of Ketones

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 63
Author(s):  
Anna Kmieciak ◽  
Marek P. Krzemiński
Keyword(s):  
Amino Alcohol ◽  
Asymmetric Reduction ◽  
Optically Active ◽  
Asymmetric Reactions ◽  
Transfer Hydrogenation ◽  
Asymmetric Transfer Hydrogenation ◽  
Active Compounds ◽  
Reduction Methods ◽  
Optically Pure ◽  
Reduction Of Ketones

Monoterpenes are optically active compounds which occur in nature. This fact makes them interesting precursors for the synthesis of optically active ligands, which can be applied in various asymmetric reactions. In this work, we present the synthesis of optically pure 2-amino-apopinan-3-ol from (−)-α-pinene. The obtained amino alcohol was used as a precursor of oxazaborolidine, which was used as catalyst in the asymmetric reduction of aryl-alkyl ketones with borane. In the second part, we transformed 2-amino-apopinan-3-ol into PHOX ligand in a three-step reaction. The complex of ruthenium precursor with PHOX ligand was used as a catalyst in the asymmetric transfer hydrogenation of aryl-alkyl ketones. Alcohols with enantiomeric excesses of up to 97% were isolated using both reduction methods.

ChemInform Abstract: Efficient Synthesis of Various Atropisomeric Amides in Optically Pure Forms and Their Application to Asymmetric Reactions.

ChemInform ◽  
2010 ◽  
Vol 31 (10) ◽  
pp. no-no
Author(s):  
Osamu Kitagawa ◽  
Shu-ichi Momose ◽  
Yoshihisa Fushimi ◽  
Takeo Taguchi
Keyword(s):  
Asymmetric Reactions ◽  
Efficient Synthesis ◽  
Optically Pure
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