349628-52-0Relevant academic research and scientific papers
Direct Asymmetric Aldol Reaction in Continuous Flow Using Gel-Bound Organocatalysts
Schmiegel, Carsten J.,Baier, Rene,Kuckling, Dirk
, p. 2578 - 2586 (2021)
Continuous flow catalysis using a microfluidic reactor with gel-bound proline organocatalysts is an attractive approach in organic synthesis due to interesting advantages such as the permanent production of catalyst-free products and the easy product isol
Asymmetric aldol reactions between cyclic ketones and benzaldehyde catalyzed by chiral Zn2+ complexes of aminoacyl 1,4,7,10- tetraazacyclododecane: Effects of solvent and additives on the stereoselectivities of the aldol products
Itoh, Susumu,Tokunaga, Takuya,Kurihara, Masayuki,Aoki, Shin
, p. 1583 - 1590 (2013)
The direct aldol reaction between cyclic ketones and 4-nitrobenzaldehyde catalyzed by chiral Zn2+ complexes of aminoacyl 1,4,7,10- tetraazacyclododecane is reported. The anti-aldol products were mainly formed in cyclohexanone/N-methylpyrrolidone(NMP)/MeOH with good diastereo- and enantioselectivity, while syn-aldol adducts were obtained as major products with good enantioselectivity in cyclohexanone/H2O and cyclohexanone/NMP/H2O. The fact that the UV/vis spectra of 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio)phenolate (Reichardt's dye) were nearly identical in these solvent systems suggests that the switch in the relative configuration of the aldol products is induced by a large excess of H2O rather than the polarity of the solvent system. Furthermore, the addition of a small amount of TFA improved the enantioselectivity of the syn-aldol adducts produced in cyclohexanone/H2O with up to 92% ee (anti/syn ratio = 30:70).
Modulating the performance of an asymmetric organocatalyst by tuning its spatial environment in a metal-organic framework
Liu, Lujia,Zhou, Tian-You,Telfer, Shane G.
, p. 13936 - 13943 (2017)
Systematically tuning the spatial environment around the active sites of synthetic catalysts is a difficult challenge. Here, we show how this can be accomplished in the pores of multicomponent metal-organic frameworks. This relies on embedding a catalytic unit in a pore of the MUF-77 framework and then tuning its environment by introducing different functional groups to the surrounding linkers. This approach benefits from the structural regularity of MUF-77, which places each component in a precise location to circumvent disorder. Prolinyl groups, which are catalytically competent toward asymmetric aldol reactions, were selected as the catalytic unit. Since every prolinyl group is positioned in an identical environment, correlations between the pore architecture and the activity of these single-site catalysts can be elucidated. Systematic engineering of the pore structure, which is achieved by installing modulator groups on the framework linkers, impacts on the reaction rate and the enantiomeric excess of the aldol products. Furthermore, the spatial environment around the proline catalyst can override its innate stereochemical preference to dictate the preferred enantiomer of the reaction product. These results offer a new way to design three-dimensional active site environments for synthetic catalysts.
Proline-Histidine Dipeptide: A Suitable Template for Generating Ion-Tagged Organocatalysts for the Asymmetric Aldol Reaction
Inani, Heena,Singh, Avtar,Bhati, Meeta,Kumari, Kiran,Kucherenko, Alexander S.,Zlotin, Sergei G.,Easwar, Srinivasan
, p. 2702 - 2712 (2021/06/02)
Proline-histidine dipeptide laid the foundation for the construction of three new ion-tagged organocatalysts, utilising the imidazole moiety of histidine for generating the quaternary species. A brief comparative investigation of the catalysts in the enam
Natural eutectogels: Sustainable catalytic systems for C-C bond formation reactions
D'Anna, Francesca,Meli, Alessandro,Ramón, Diego J.,Rizzo, Carla,Saavedra, Beatriz
supporting information, p. 6555 - 6565 (2021/09/10)
Natural eutectogels were prepared by combining the properties of amino acids with the ones of deep eutectic solvents. The soft materials obtained were fully characterised by determining the gel-sol transition temperatures and analysing the mechanical and
Pro-phe derivatives as organocatalysts in asymmetric aldol reaction
Aydogan, Feray,Karaoglu, Merve,Yolacan, Cigdem
supporting information, p. 233 - 239 (2021/03/19)
The aldol reaction which is the most important one among the C-C bond forming reactions, is widely used by synthetic organic chemists to obtain β-hydroxycarbonyl compounds which are important starting components for biologically active compounds in optica
Nanocellulose enriches enantiomers in asymmetric aldol reactions
Habaki, Xin,Kanomata, Kyohei,Kitaoka, Takuya,Ranaivoarimanana, Naliharifetra Jessica,Uto, Takuya,Yui, Toshifumi
, p. 37064 - 37071 (2020/10/28)
Cellulose nanofibers obtained from wood pulp by TEMPO-mediated oxidation acted as a chiral enhancer in direct aldol reactions of 4-nitrobenzaldehyde and cyclopentanone with (S)-proline as an organocatalyst. Surprisingly, catalytically inactive TEMPO-oxidi
L-proline/cholesterol and diosgenin based thiourea cooperative system for the direct asymmetric aldol reaction in the presence of water
Eymur, Serkan,Ta?ci, Enis,Uyanik, Arzu,Yilmaz, Mustafa
, p. 1278 - 1284 (2020/11/20)
A series of cholesterol and based hydrophobic urea and thiourea compounds were synthesized and successfully used as a cocatalyst for L-proline catalyzed aldol reactions in the presence of water. The anticonfigured products were obtained with good yields (up to 94%), high diastereoselectivities (up to 95:5), and high enantiomeric excesses (up to 93% ee). The successful results for catalytic efficiency of L-proline in the presence of water reveal the importance of the hydrophobic nature of cholesterol and diosgenin parts of thiourea on the reactivity and selectivity in the presence of water.
Chiral proline sulfonamide bifunctional catalyst and preparation method and application thereof
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Paragraph 0097-0101, (2020/08/17)
The invention discloses a novel chiral sulfonamide bifunctional catalyst and a preparation method and application thereof. The catalyst comprises a compound A or a compound B. The molecular structureof the compound A is shown as a formula (I) which is des
Evaluation of Amino Nitriles and an Amino Imidate as Organo?-catalysts in Aldol Reactions
Brown, Alexander J.,Clarke, Paul A.,Vagkidis, Nikolaos
supporting information, p. 4106 - 4112 (2019/10/28)
The efficiency of l -valine and l -proline nitriles and a tert -butyl?- l -proline imidate as organocatalysts for the aldol reaction have been evaluated. l -Valine nitrile was found to be a syn -selective catalyst, while l -proline nitrile was found to be anti -selective, and gave products in modest to good enantioselectivities. tert -Butyl l -proline imidate was found to be a very efficient catalyst in terms of conversion of starting reagents to products, and gave good anti -selectivity. The enantioselectivity of the tert -butyl l -proline imidate was found to be good to excellent, with products being formed in up to 94percent enantiomeric excess.
