Catalytic cascade aldol–cyclization of tertiary ketone enolates for enantioselective synthesis of keto-esters with a C–F quaternary stereogenic center

2016 ◽  
Vol 14 (30) ◽  
pp. 7295-7303 ◽  
Author(s):  
Wanxing Sha ◽  
Lijun Zhang ◽  
Wenzhong Zhang ◽  
Haibo Mei ◽  
Vadim A. Soloshonok ◽  
...  
Keyword(s):  
Cascade Reaction ◽  
Enantioselective Synthesis ◽  
Keto Esters ◽  
Aldol Cyclization ◽  
Ketone Enolates ◽  
Stereogenic Center

The first enantioselective catalytic aldol–cyclization cascade reaction of detrifluoroacetylatively in situ generated tertiary enolates with methyl 2-formylbenzoate is reported.

Brønsted acid-catalyzed, enantioselective synthesis of 1,4-dihydroquinoline-3-carboxylates via in situ generated ortho-quinone methide imines

2017 ◽  
Vol 15 (17) ◽  
pp. 3706-3716 ◽  
Author(s):  
Tomáš Hodík ◽  
Christoph Schneider
Keyword(s):  
Phosphoric Acid ◽  
Acid Catalysis ◽  
Nitrogen Heterocycles ◽  
Enantioselective Synthesis ◽  
Quinone Methide ◽  
Keto Esters ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Straightforward Approach

A straightforward approach toward the synthesis of a broad range of 1,4-dihydroquinoline-3-carboxylates is described. Under phosphoric acid catalysis in situ-generated ortho-quinone methide imines reacted with β-keto esters to form the nitrogen heterocycles with good chemical yields and enantioselectivities.

Enantioselective Synthesis of Difluoroalkylated Isoindolinones via Chiral Spirocyclic Phosphoric Acid Catalyzed Mannich-Type Reaction

Synlett ◽  
2020 ◽  
Author(s):  
Xufeng Lin ◽  
Lei Wang ◽  
Jialing Zhong
Keyword(s):  
Phosphoric Acid ◽  
Enantioselective Synthesis ◽  
Type Reaction ◽  
Acid Catalyzed ◽  
High Yields ◽  
Stereogenic Center ◽  
Facile Route

AbstractAn enantioselective Mannich-type reaction of in situ generated cyclic ketimines with difluoroenoxysilanes catalyzed by chiral spirocyclic phosphoric acid has been developed. This methodology provides a facile route to difluoroalkyl-substituted chiral isoindolinones bearing a quaternary stereogenic center in high yields and up to 96% enantioselectivity.

A Short Enantioselective Synthesis of (S)-Levetiracetam Through Direct Pd-Catalyzed Asymmetric N-Allylation of Methyl 4-Aminobutyrate

Synlett ◽  
2021 ◽  
Author(s):  
Dominik Albat ◽  
Jörg-Martin Neudörfl ◽  
Hans-Günther Schmalz
Keyword(s):  
Antiepileptic Drug ◽  
Tartaric Acid ◽  
Enantioselective Synthesis

An exceedingly short and enantioselective synthesis of the antiepileptic drug (S)-levetiracetam was elaborated. As the chirogenic key step a Pd-catalyzed asymmetric N-allylation of methyl 4-aminobutyrate was achieved in the presence of only 1 mol% of a catalyst prepared in situ from [Pd(allyl)Cl]2 and the tartaric acid-derived C2-symmetric diphosphane ligand (S,S)-iPr-MediPhos).

ChemInform Abstract: Enantioselective Direct Vinylogous Aldol-Cyclization Cascade Reaction Between β,γ-Unsaturated Amides and o-Quinones.

ChemInform ◽  
2016 ◽  
Vol 47 (46) ◽  
Author(s):  
Yu Jiang ◽  
Jun-Hao Fu ◽  
Tian-Ze Li ◽  
Feng Sha ◽  
Xin-Yan Wu
Keyword(s):  
Cascade Reaction ◽  
Aldol Cyclization

scholarly journals Application of an enzymatic cascade reaction for the synthesis of the emeraldine salt form of polyaniline

2021 ◽  
Author(s):  
Minoru Kurisu ◽  
Reinhard Kissner ◽  
Masayuki Imai ◽  
Peter Walde
Keyword(s):  
Cascade Reaction ◽  
Emeraldine Salt ◽  
Salt Form ◽  
Experimental Conditions ◽  
Peroxidase Isoenzyme ◽  
Large Unilamellar Vesicles ◽  
Dark Green ◽  
Catalyzed Oxidation ◽  
Reference Reaction

AbstractThe synthesis of the emeraldine salt form of polyaniline (PANI-ES) from aniline with Aspergillus sp. glucose oxidase (GOD), d-glucose, dissolved O2, and horseradish peroxidase isoenzyme C (HRPC) in the presence of large unilamellar vesicles of AOT (sodium bis-(2-ethylhexyl)sulfosuccinate) as templates at pH = 4.3 and T ~ 25 °C was investigated in a systematic way. In this cascade reaction mixture, the oxidation of aniline is catalyzed by HRPC with H2O2 that is formed in situ as byproduct of the GOD-catalyzed oxidation of d-glucose with O2. Under the elaborated experimental conditions which we considered ideal, the formation of PANI-ES products is evident, as judged by UV/Vis/NIR and EPR measurements. Comparison was made with a reference reaction, which was run under similar conditions with added H2O2 instead of GOD and d-glucose. Although the reference reaction was found to be superior, with the cascade reaction, PANI-ES products can still be obtained with high aniline conversion (> 90%) within 24 h as stable dark green PANI-ES/AOT vesicle dispersion. Our results show that the in situ formation of H2O2 does not prevent the inactivation of HRPC known to occur in the reference reaction. Moreover, the GOD used in the cascade reaction is inactivated as well by polymerization intermediates.

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