• Efficient ball-mill procedure in the ‘green’ asymmetric

    09-09-2011· The organocatalytic activity of (S)-proline-based dipeptides 1a–c has been evaluated in the asymmetric aldol reaction between representative ketones with various aromatic aldehydes under solvent-free conditions in a ball mill.In particular, the methyl ester of (S)-proline-(S)-tryptophan, (S,S)-1c, proved to be an efficient organocatalyst, and the aldol reaction

    Efficient ball-mill procedure in the ‘green’ asymmetric

    Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water Tetrahedron, 2011 Eusebio Juaristi

    efficient ball mill procedure in the ‘green’ asymmetric

    Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water. Tetrahedron 2011, DOI: 10.1016/j.tet.2011.06.042. Wenbo Huang, Hua Tian, Hao Xu, Liangyu Zheng, Qingwen Liu, Suoqin Zhang. More

    Efficient ball-mill procedure in the ‘green’ asymmetric

    Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by ( S)-proline-containing dipeptides in the presence of water

    ChemInform Abstract: Efficient Ball-Mill Procedure in the

    ChemInform Abstract: Efficient Ball-Mill Procedure in the ′Green′ Asymmetric Aldol Reaction Organocatalyzed by (S)-Proline-Containing Dipeptides in the Presence of Water.

    A Green and Efficient Asymmetric Aldol Reaction Catalyzed

    A chiral anion modified ionic liquid derived from L ‐proline proves as a green and efficient asymmetric organocatalyst for direct asymmetric aldol reactions in [BMIm]BF 4 at room temperature. The corresponding aldol products with moderate to good isolated yields (up to 99 %), anti ‐diastereoselectivities (up to 97:3), and excellent enantioselectivities (up to 99 % ee )

    green aldol ndensation by ball mill method

    green aldol condensation by ball mill method. In the H method, a ball bearing is placed inside a vessel that is as 1,2,3,6tetrahydrobenzaldehyde the dimeric ester is the major product and we observed no product resulting from the aldol condensation.,unsaturated systems such as Ball milling was carried out in a 8000M SpexCertiprep Mixer/Mill.

    Asymmetric Aldol Reaction Organocatalyzed by (S)-Proline

    Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water. Tetrahedron 2011,67 (36),6953-6959.

    A Highly Efficient Solvent-Free Asymmetric Direct Aldol

    Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water. Tetrahedron 2011,67 (36),6953-6959.

    Efficient ball-mill procedure in the ‘green’ asymmetric

    Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by ( S)-proline-containing dipeptides in the presence of water

    10.1016/j.tet.2011.06.042 DeepDyve

    The desired aldol products were obtained in high yields (up to 94%) and good enantioselectivities (up to 97% ee). 17a In addition, Li and co-workers examined dipeptide ( 1c -OH) in the asymmetric aldol reaction of different ketones and aldehydes in solid phase media (Al 2 O 3 ), using 1,4-diazabicyclo[2.2.2]octane as additive, observing moderate to high reaction yields

    A Green and Efficient Asymmetric Aldol Reaction

    A chiral anion modified ionic liquid derived from L ‐proline proves as a green and efficient asymmetric organocatalyst for direct asymmetric aldol reactions in [BMIm]BF 4 at room temperature. The corresponding aldol products with moderate to good isolated yields (up to 99 %), anti ‐diastereoselectivities (up to 97:3), and excellent enantioselectivities (up to 99 % ee )

    efficient ball mill procedure in the aldol reaction

    efficient organocatalyst studied promoting the direct aldol reaction of reaction times and result in simple and efficient workup procedures. . efficacy of catalyst 1d was similar when the reaction was performed in a ball mill[9a,9b] (Table 1,.

    green aldol ndensation by ball mill method

    green aldol condensation by ball mill method. In the H method, a ball bearing is placed inside a vessel that is as 1,2,3,6tetrahydrobenzaldehyde the dimeric ester is the major product and we observed no product resulting from the aldol condensation.,unsaturated systems such as Ball milling was carried out in a 8000M SpexCertiprep Mixer/Mill.

    Asymmetric Aldol Reaction Organocatalyzed by (S)

    Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water. Tetrahedron 2011,67 (36),6953-6959.

    A Highly Efficient Solvent-Free Asymmetric Direct Aldol

    Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water. Tetrahedron 2011,67 (36),6953-6959.

    A green look at the aldol reaction Green Chemistry

    The aldol reaction is one of the most powerful and best known C–C forming synthetic reactions, universally present in basic and advanced organic chemistry texts and amply reviewed in organic synthetic books and series. 1–4 The reaction has industrial relevance either in bulk production, or in the fine chemical and pharmaceutical industry. 5 The aldol reaction has a particular

    Solvent-free enantioselective organocatalyzed aldol reactions

    solvent media. The first solvent-free intermolecular aldol reaction involved the use of a ball mill [22]. This technique [23] is widely applied in grinding minerals and solids into fine particles and it was used in this transformation in order to enhance the efficient mixing of reagents and the catalyst. The best results

    Polymer‐Immobilized Pyrrolidine‐Based Chiral Ionic Liquids

    José G. Hernández and Eusebio Juaristi, Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water, Tetrahedron, 67, 36, (6953), (2011).

    Asymmetric Aldol Reaction Organocatalyzed by (S)

    Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water. Tetrahedron 2011,67 (36),6953-6959.

    Solvent-free asymmetric aldol reaction organocatalyzed

    27-01-2021· An efficient, solvent-free ball-milling protocol for the asymmetric aldol reaction between cyclohexanone and cyclopentanone with various aromatic aldehydes using a novel series of (S)-proline-containing dipeptides and thiodipeptides 1aef as organocatalysts is reported. In general, (S)-proline-containing thiodipeptides proved to be better organocatalysts relative to their analogous amides.

    Mechanochemistry assisted asymmetric organocatalysis: A

    Scheme 4: Asymmetric aldol reaction assisted by ball-milling catalysed by dipeptides (A) with III and (B) with IV. The methyl ester of (S)-proline-(S)-tryptophan (IV) was shown to be an efficient organocatalyst for asymmetric aldol reactions of ketones with aromatic aldehydes in the presence of water by using HSBM (Scheme€4) [37].

    efficient ball mill procedure in the green asymmetric

    Home > efficient ball mill procedure in the green asymmetric aldol reaction. efficient ball mill procedure in the green asymmetric aldol reaction. CrossRef Cited By Search Results : nature. Find information of efficient ball mill procedure in the green asymmetric aldol reaction,

    Solvent-free enantioselective organocatalyzed aldol reactions

    solvent media. The first solvent-free intermolecular aldol reaction involved the use of a ball mill [22]. This technique [23] is widely applied in grinding minerals and solids into fine particles and it was used in this transformation in order to enhance the efficient mixing of reagents and the catalyst. The best results

    Polymer‐Immobilized Pyrrolidine‐Based Chiral Ionic

    José G. Hernández, Eusebio Juaristi, Efficient ball-mill procedure in the ‘green’ asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water, Tetrahedron, 10.1016/j.tet.2011.06.042, 67, 36, (6953-6959), (2011).

    A Highly Efficient Solvent-Free Asymmetric Direct Aldol

    Three different methods are assayed: simple conventional magnetic stirring, magnetic stirring after previous dissolution in THF and evaporation, and ball mill technique. These procedures allow one to reduce not only the amount of required ketone to 2 equiv but also the reaction time to give the aldol products with regio-, diastereo-, and enantioselectivities comparable to those in organic or aqueous

    Bio-renewable enantioselective aldol reaction in natural

    Introduction Organocatalyzed enantioselective reactions 1 have been proposed as ideal green processes, 2 as these procedures use only small organic molecules as catalysts in the absence of any type of metal. The epitome, among these processes, is the enantioselective cross-aldol reaction. 3 However, a close look at the reaction, as well as the synthetic protocols, forecasts some aspects that

    Water versus Solvent-free Conditions for the

    reaction times and result in simple and efficient workup procedures.[9] For these reasons, organocatalyzed aldol reactions under solvent-free conditions or employing water as solvent have become a highly pursued goal in green chemistry. Following our studies in the use of prolineamide-derived organocatalysts as efficient

    Asymmetric Catalysis Home ICM

    [23] Hernández J.G., Juaristi E., Efficient ball-mill procedure inthe ‘green’ asymmetric aldol reaction organocatalyzed by(S)-proline-containing dipeptides in the presence of

    Mechanochemistry assisted asymmetric organocatalysis: A

    Scheme 4: Asymmetric aldol reaction assisted by ball-milling catalysed by dipeptides (A) with III and (B) with IV. The methyl ester of (S)-proline-(S)-tryptophan (IV) was shown to be an efficient organocatalyst for asymmetric aldol reactions of ketones with aromatic aldehydes in the presence of water by using HSBM (Scheme€4) [37].

    Solvent-free enantioselective organocatalyzed aldol reactions

    solvent media. The first solvent-free intermolecular aldol reaction involved the use of a ball mill [22]. This technique [23] is widely applied in grinding minerals and solids into fine particles and it was used in this transformation in order to enhance the efficient mixing of reagents and the catalyst. The best results

    Earthworms as a Biocatalyst: In Asymmetric Aldol

    The asymmetric direct aldol reaction as one of the most powerful carbon-carbon bond formation methods has become one of the central study issues in organic synthesis. 11 In recent years, a lot of successful metal catalysts and organocatalysts for direct asymmetric aldol reactions have been reported with high efficiency and enantioselectivity, 12 including some methods under

    Bio-renewable enantioselective aldol reaction in natural

    Introduction Organocatalyzed enantioselective reactions 1 have been proposed as ideal green processes, 2 as these procedures use only small organic molecules as catalysts in the absence of any type of metal. The epitome, among these processes, is the enantioselective cross-aldol reaction. 3 However, a close look at the reaction, as well as the synthetic protocols, forecasts

    Water versus Solvent-free Conditions for the

    reaction times and result in simple and efficient workup procedures.[9] For these reasons, organocatalyzed aldol reactions under solvent-free conditions or employing water as solvent have become a highly pursued goal in green chemistry. Following our studies in the use of prolineamide-derived organocatalysts as efficient

    Aldol Reaction Chemistry LibreTexts

    A useful carbon-carbon bond-forming reaction known as the Aldol Reaction is yet another example of electrophilic substitution at the alpha carbon in enolate anions. The fundamental transformation in this reaction is a dimerization of an aldehyde (or ketone) to a beta-hydroxy aldehyde (or ketone) by alpha C–H addition of one reactant molecule to the carbonyl group of

    Aldol condensation Wikipedia

    Aldol condensations are important in organic synthesis, because they provide a good way to form carbon–carbon bonds. For example, the Robinson annulation reaction sequence features an aldol condensation; the Wieland–Miescher ketone product is an important starting material for many organic syntheses. Aldol condensations are also commonly discussed in university level

    Highly Diastereo‐ and Enantioselective Direct Aldol

    List, Lerner, and Barbas discovered the proline‐mediated aldol reaction in 2000. 13 Since then, many organocatalysts have been developed for several asymmetric reactions. 6,14 Proline is capable of catalyzing the direct aldol reaction in polar organic solvents such as DMSO and DMF. 13,15,16 Recently, Bolm and co‐workers reported that proline catalyzes a solvent‐free asymmetric

    Разработка каталитических систем для осуществления

    132. Hernández J.G., Juaristi E. Efficient ball-mill procedure in the 'green' asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water// Tetrahedron Lett., 2011, Vol. 67, № 36, P. 6953-6959 133.

    Benzoin condensation Wikipedia

    The benzoin addition is an addition reaction involving two aldehydes.The reaction generally occurs between aromatic aldehydes or glyoxals. The reaction produces an acyloin.In the classic application benzaldehyde is converted to benzoin.. The benzoin condensation was first reported in 1832 by Justus von Liebig and Friedrich Wöhler during their research on bitter almond oil.

 

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