2,4-Dinitrophenol as an Effective Cocatalyst: Greatly Improving the Activities and Enantioselectivities of Primary Amine Organocatalysts for Asymmetric Aldol Reactions

2009 ◽  
Vol 74 (6) ◽  
pp. 2541-2546 ◽  
Author(s):  
Chao-Shan Da ◽  
Li-Ping Che ◽  
Qi-Peng Guo ◽  
Feng-Chun Wu ◽  
Xiao Ma ◽  
...  
Keyword(s):  
Primary Amine ◽  
Aldol Reactions ◽  
Asymmetric Aldol

In Situ Formed Bifunctional Primary Amine-Imine Catalyst for Asymmetric Aldol Reactions of α-Keto Esters

2011 ◽  
Vol 17 (30) ◽  
pp. 8281-8284 ◽  
Author(s):  
Xi Zhu ◽  
Aijun Lin ◽  
Ling Fang ◽  
Wei Li ◽  
Chengjian Zhu ◽  
...  
Keyword(s):  
Primary Amine ◽  
Aldol Reactions ◽  
Asymmetric Aldol ◽  
Keto Esters

scholarly journals Νέοι οργανοκαταλύτες και εφαρμογές τους σε ασύμμετρους οργανικούς μετασχηματισμούς

2014 ◽  
Author(s):  
Μιχαήλ Τσάκος
Keyword(s):  
Catalytic Activity ◽  
Asymmetric Catalysis ◽  
Primary Amine ◽  
Aldol Reactions ◽  
Henry Reaction ◽  
Asymmetric Aldol ◽  
Asymmetric Transformations ◽  
Tert Butyl ◽  
Proline Derivatives ◽  
Asymmetric Michael Reaction

Nowadays, organocatalysis constitutes the third pillar of asymmetric catalysis, alongside transition metal catalysis and biocatalysis. The definition of organocatalysis is the use of low molecular weight organic molecules as catalysts in organic transformations.The goals of this thesis were on one hand, to synthesize novel organocatalysts based on natural aminoacids and evaluate their activity in known asymmetric transformations, and on the other hand, to exploit organocatalysis in general in order to accomplish unprecedented asymmetric reactions.In the context of synthesizing novel organocatalysts, we synthesized primary amine-thioureas based on di-tert-butyl aspartate and a chiral 1,2-diamine and we studied their catalytic activity in the asymmetric Michael reaction between ketones and nitroalkenes or nitrodienes. Σhe primary amine-thiourea consisting of di-tert-butyl aspartate and (1R, 2R)-diphenylethylene-1,2-diamine, was found to be a very powerful organocatalyst exhibiting remarkable results in the asymmetric Michael addition of methyl ketones to nitroalkenes or nitrodienes. The aforementioned organocatalyst was employed in the key-step of the asymmetric synthesis of the commercially available drug Baclofen.In addition, organocatalysts known in the literature were employed in order to develop unprecedented asymmetric transformations, such as the domino Michael-Henry reaction between 1,4-cyclohexanedione and nitroalkenes and the asymmetric Mannich addition of 2-chloro-1,3-dicarbonyl compounds or nitroalkanes to oxindole derived ketimines.Furthermore, a segment of this thesis focused on the synthesis of proline derivatives properly modified for immobilization on carbon nanotubes, in order to evaluate their catalytic activity in asymmetric aldol reactions.

(S)-5-prolylamide-triazole Organocatalyst for Direct Asymmetric Aldol Reactions

2013 ◽  
Vol 17 (14) ◽  
pp. 1563-1568 ◽  
Author(s):  
Ling Liu ◽  
Min-Na Gao ◽  
Yang Li ◽  
Zhen Li ◽  
Liping Song ◽  
...  
Keyword(s):  
Aldol Reactions ◽  
Asymmetric Aldol

ChemInform Abstract: Organocatalytic Asymmetric Aldol Reactions Mediated by a Cysteine-Derived Prolinamide.

ChemInform ◽  
2008 ◽  
Vol 39 (48) ◽  
Author(s):  
Ricardo S. Schwab ◽  
Fabio Z. Galetto ◽  
Juliano B. Azeredo ◽  
Antonio L. Braga ◽  
Diogo S. Luedtke ◽  
...  
Keyword(s):  
Aldol Reactions ◽  
Asymmetric Aldol

Synthesis and evaluation of (S)-proline-containing dipeptidic organocatalysts bound to MBHA resin in asymmetric aldol reactions

2015 ◽  
Vol 56 (44) ◽  
pp. 6047-6051 ◽  
Author(s):  
Elizabeth Machuca ◽  
Giovanna Granados ◽  
Bruno Hinojosa ◽  
Eusebio Juaristi
Keyword(s):  
Aldol Reactions ◽  
Asymmetric Aldol

Intramolecular hydrogen bonding guides a cationic amphiphilic organocatalyst to highly stereoselective aldol reactions in water

RSC Advances ◽  
2015 ◽  
Vol 5 (77) ◽  
pp. 62331-62335 ◽  
Author(s):  
Ángel M. Valdivielso ◽  
Alba Catot ◽  
Ignacio Alfonso ◽  
Ciril Jimeno
Keyword(s):  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Structural Motif ◽  
Aldol Reactions ◽  
Asymmetric Aldol ◽  
Neutral Ph ◽  
Intramolecular Hydrogen

A novel amphiphilic acylguanidine organocatalyst using intramolecular hydrogen bonding as a key structural motif is efficient for asymmetric aldol reactions of ketones in water at neutral pH.

Non-linear effects in acyclic amino acid-catalyzed direct asymmetric aldol reactions

2006 ◽  
Vol 47 (37) ◽  
pp. 6657-6661 ◽  
Author(s):  
Pawel Dziedzic ◽  
Weibiao Zou ◽  
Ismail Ibrahem ◽  
Henrik Sundén ◽  
Armando Córdova
Keyword(s):  
Amino Acid ◽  
Aldol Reactions ◽  
Asymmetric Aldol ◽  
Non Linear ◽  
Linear Effects ◽  
Acid Catalyzed

Asymmetric Aldol Reactions under Normal and Inverse Addition Modes of the Reagents.

ChemInform ◽  
2007 ◽  
Vol 38 (44) ◽  
Author(s):  
Saumen Hajra ◽  
Aswini Kumar Giri ◽  
Ananta Karmakar ◽  
Snehadrinarayan Khatua
Keyword(s):  
Aldol Reactions ◽  
Asymmetric Aldol
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