Journal ArticleDOI
A phosphotungstic acid-supported multifunctional organocatalyst containing 9-amino(9-deoxy)epi-cinchonidine and Brønsted acid and its application in asymmetric aldol reaction
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TLDR
It was found that the arm length and acid capacity had significant effects on the cooperative catalysis of CDNH2 and Brosted acid in the aldol reaction, and the catalysts could be readily recovered in quantitative yield by centrifugation and possessed good reusability with no significant loss of catalytic performance in the five consecutive asymmetric a Aldol reactions.Abstract:
A novel type of supported multifunctional organocatalyst CDNH2(n)–HPW combined 9-amino(9-deoxy)epi-cinchonidine (CDNH2) with Bronsted acid in the backbone of phosphotungstic acid was developed via facile precipitation of sodium tungstate with organophosphonic acid The aldol addition of cyclohexanone to o, m or p-substituted benzaldehydes bearing electron-withdrawing substituents (–X and –NO2) afforded good yields (71–96%) and excellent stereoselectivities (anti/syn = 94/6–98/2, 87–97% ee) It was found that the arm length (n) and acid capacity had significant effects on the cooperative catalysis of CDNH2 and Brosted acid in the aldol reaction After the completion of the aldol reaction, the catalysts could be readily recovered in quantitative yield by centrifugation and possessed good reusability with no significant loss of catalytic performance in the five consecutive asymmetric aldol reactionsread more
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Journal ArticleDOI
Catalytic enantioselective aldol reactions
TL;DR: This review article is organized under the categories of catalytic enantioselective aldol reactions of preformed enolates, catalyticEnantioseLECTive direct-type a Aldol reactions using chiral metal catalysts, and catalytic Enantioselections in aqueous media.
Journal ArticleDOI
Recent developments in next generation (S)-proline-derived chiral organocatalysts
TL;DR: In this paper, an overview of the development of diamine analogs of privileged (S)-prolinols as organocatalysts is presented, and the remarkable influence of solvate ionic liquids as well as the usage of other types of ionic liquid that results in a significant improvement of the catalytic activity of proline is described.
Journal ArticleDOI
Quaternary Ammonium Functionalized Polyacrylonitrile Fiber Supported Phosphotungstic Acid as Efficient Heterogeneous Catalyst: Hydrophobic Tuning of the Catalytic Microenvironment
TL;DR: In this article, 13 amine or quaternary ammonium functionalized polyacrylonitrile fiber (PANF) supported PTA catalysts were designed and prepared, and their catalytic activities were screened by choosing condensation/annulation tandem synthesis of 2,3-dihydroquinazolin-4(1H)-one compound via C-N bond formation between 2-aminobenzamide and p-chlorobenzaldehyde as a model reaction.
Journal ArticleDOI
Selective removal of 1,2‐propanediol and 1,2‐butanediol from bio‐ethylene glycol by catalytic reaction
Ai Shuo,Mingyuan Zheng,Jiang Yu,Xiaofeng Yang,Xinsheng Li,Jifeng Pang,Joby Sebastian,Weizhen Li,Aiqin Wang,Xiaodong Wang,Tao Zhang +10 more
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Self-Assembly of Amphiphilic Dipeptide with Homo- and Heterochiral Centers and Their Application in Asymmetric Aldol Reaction.
TL;DR: It was found that both of the diastereomeric dipeptides can easily self-assemble into organogels with nanofibers and showed higher enantioselectivity than the L–D isomer.
References
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TL;DR: Mise au point comportant des definitions generales et la terminologie, la methodologie utilisee, les procedes experimentaux, les interpretations des donnees d'adsorption, les determinations de l'aire superficielle, and les donnes sur la mesoporosite et la microporosite.
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