Sc(III)-Catalyzed Enantioselective Addition of Thiols to α,β-Unsaturated Ketones in Neutral Water

2011 ◽  
Vol 13 (9) ◽  
pp. 2150-2152 ◽  
Author(s):  
Simona Bonollo ◽  
Daniela Lanari ◽  
Ferdinando Pizzo ◽  
Luigi Vaccaro
Keyword(s):  
Unsaturated Ketones ◽  
Neutral Water ◽  
Enantioselective Addition

ChemInform Abstract: Sc(III)-Catalyzed Enantioselective Addition of Thiols to α,β-Unsaturated Ketones in Neutral Water.

ChemInform ◽  
2011 ◽  
Vol 42 (37) ◽  
pp. no-no
Author(s):  
Simona Bonollo ◽  
Daniela Lanari ◽  
Ferdinando Pizzo ◽  
Luigi Vaccaro
Keyword(s):  
Unsaturated Ketones ◽  
Neutral Water ◽  
Enantioselective Addition

Enantioselective addition of selenosulfonates to α,β-unsaturated ketones

2018 ◽  
Vol 16 (16) ◽  
pp. 2893-2901 ◽  
Author(s):  
Shilong Luo ◽  
Nan Zhang ◽  
Zhen Wang ◽  
Hailong Yan
Keyword(s):  
Unsaturated Ketones ◽  
Enantioselective Addition ◽  
First Time

An efficient organo-catalyzed enantioselective addition of selenosulfonates to α,β-unsaturated ketones was developed for the first time.

scholarly journals Modular synthesis of chiral 1,2-dihydropyridines via Mannich/Wittig/cycloisomerization sequence that internally reuses waste

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bo-Shuai Mu ◽  
Xiao-Yuan Cui ◽  
Xing-Ping Zeng ◽  
Jin-Sheng Yu ◽  
Jian Zhou
Keyword(s):  
Enantioselective Synthesis ◽  
Side Reactions ◽  
Structural Components ◽  
Chiral Amine ◽  
Low Concentration ◽  
Unsaturated Ketones ◽  
Modular Synthesis ◽  
Enantioselective Addition ◽  
Product Water ◽  
Hydrolysis Of

Abstract1,2-Dihydropyridines are valuable and reactive synthons, and particularly useful precursors to synthesize piperidines and pyridines that are among the most common structural components of pharmaceuticals. However, the catalytic enantioselective synthesis of structurally diverse 1,2-dihydropyridines is limited to enantioselective addition of nucleophiles to activated pyridines. Here, we report a modular organocatalytic Mannich/Wittig/cycloisomerization sequence as a flexible strategy to access chiral 1,2-dihydropyridines from N-Boc aldimines, aldehydes, and phosphoranes, using a chiral amine catalyst. The key step in this protocol, cycloisomerization of chiral N-Boc δ-amino α,β-unsaturated ketones recycles the waste to improve the yield. Specifically, recycling by-product water from imine formation to gradually release the true catalyst HCl via hydrolysis of SiCl4, whilst maintaining a low concentration of HCl to suppress side reactions, and reusing waste Ph3PO from the Wittig step to modulate the acidity of HCl. This approach allows facile access to enantioenriched 2-substituted, 2,3- or 2,6-cis-disubstituted, and 2,3,6-cis-trisubstituted piperidines.

1,4-Reductions of α,β-Unsaturated Ketones and Aldehydes via in situ Generated Hydridocuprates

Synlett ◽  
1989 ◽  
Vol 1989 (01) ◽  
pp. 64-66 ◽  
Author(s):  
Bruce H. Lipshutz ◽  
Christopher S. Ung ◽  
Saumitra Sengupta
Keyword(s):  
Unsaturated Ketones

Regio-, Stereo- and Enantioselective α-Addition of Carbonyl Nucleo-philes to Allenamides Catalyzed by a Synergistic Copper/Enamine System

2020 ◽  
Author(s):  
Rémi Blieck ◽  
Sebastien Lemouzy ◽  
Marc Taillefer ◽  
Florian Monnier
Keyword(s):  
Catalytic System ◽  
Secondary Amine ◽  
Primary Amine ◽  
Synergistic Catalysis ◽  
Enantioselective Addition ◽  
Amine Catalysts

A dual copper/enamine catalytic system is found to enable an intermolecular enantioselective α-addition of various carbonyl nucleophiles to allenamides. Secondary amine catalysts allowed the highly enantioselective addition of aldehydes, while using primary amine catalysts led to the enantioselective addition of ketoester nucleophiles. The process was found to be highly regio-, stereo- and enantio-selective and represented the first allene hydrofunctionalization using an synergistic catalysis involving copper

Structural analysis of oligomeric fructans from excised leaves of Lolium temulentum

2020 ◽  
Author(s):  
Ian Sims ◽  
CJ Pollock ◽  
R Horgan
Keyword(s):  
Mass Spectrometry ◽  
Structural Analysis ◽  
Higher Plants ◽  
Water Soluble ◽  
Lolium Temulentum ◽  
Neutral Water ◽  
Alditol Acetates ◽  
Partially Methylated

Individual fructan tri-, tetra- and pentasaccharide isomers in neutral, water-soluble extracts from Lolium temulentum were purified and the linkages present in these isomeric oligosaccharides were analysed by combined GC-mass spectrometry of partially methylated alditol acetates. 1-Kestose and neokestose were the most abundant trisaccharides with 6-kestose present in much lower amounts. Analysis of isomers of DP 4 and 5 showed that multiple linkage types were present with structures based on all three trisaccharides. Oligosaccharides based on neokestose but with 2,6 linkages between adjacent fructose residues have not been previously detected in higher plants. © 1992.

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