Functionalized Chiral Ionic Liquids as Highly Efficient Asymmetric Organocatalysts for Michael Addition to Nitroolefins

Luo, Sanzhong; Mi, Xueling; Zhang, Long; Liu, Song; Xu, Hui; Cheng, Jiang

doi:10.1002/anie.200600048

Cited by 443 publications

(127 citation statements)

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“…7 Luo and co-workers reported the preparation of chiral imidazolium salts derived from proline. 8 Inspired by their work, we prepared two types of chiral pyrrolidine-substituted imidazolium ¡-cetylpolyoxyethylene(10) ether sulfate, and found that (R)-3-butyl-2-methyl-1-(pyrrolidin-2-ylmethyl)-1H-imidazol-3-ium ¡-cetylpolyoxyethylene(10) ether sulfate (D-ProMe) derived from D-proline worked as an excellent activating agent for lipase PS (Figure 1). 9 An extraordinary acceleration was accomplished with perfect enantioselectivity for the D-ProMe-PS-catalyzed reaction, and a reaction 58 times faster (vs. lipase PS) was recorded.…”

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confidence: 99%

Synergetic Activation of Lipase by an Amino Acid with Alkyl–PEG Sulfate Ionic Liquid

et al. 2013

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The synergetic effect of amino acids and an ionic liquid, 1-butyl-2,3-dimethylimidazolium ¡-cetylpolyoxyethylene(10) ether sulfate (IL1), as coating materials on lipase was discovered: coating on lipase PS using a certain amino acid with IL1 was found to be very effective for accelerating the lipase-catalyzed transesterification of secondary alcohols while maintaining perfect enantioselectivity.Lipases are among the most widely used enzymes applicable for various substrates; however, the reaction rate and enantioselectivity depend significantly on both the substrates and reaction media: the reaction rates are generally dependent on the reaction media, and very slow or poorly enantioselective reactions are sometimes obtained. 1We have been investigating enzymatic reactions in the ionic liquid (IL) solvent system and have established that various types of ILs are applicable as solvents for biochemical reactions. 24 We further developed a powerful method for the activation of lipase protein through coating with an ionic liquid: Burkholderia cepacia lipase coated with the ionic liquid, 1-butyl-2,3-dimethylimidazolium ¡-cetylpolyoxyethylene(10) ether sulfate (IL1), 5,6 (IL1-PS), displayed excellent reactivity for many substrates in conventional organic solvents 5 and ionic liquids. 7Luo and co-workers reported the preparation of chiral imidazolium salts derived from proline. 8 Inspired by their work, we prepared two types of chiral pyrrolidine-substituted imidazolium ¡-cetylpolyoxyethylene(10) ether sulfate, and found that (R)-3-butyl-2-methyl-1-(pyrrolidin-2-ylmethyl)-1H-imidazol-3-ium ¡-cetylpolyoxyethylene(10) ether sulfate (D-ProMe) derived from D-proline worked as an excellent activating agent for lipase PS (Figure 1). 9 An extraordinary acceleration was accomplished with perfect enantioselectivity for the D-ProMe-PS-catalyzed reaction, and a reaction 58 times faster (vs. lipase PS) was recorded.9 However, more simple coating materials need to be developed for the activation of lipase. We herein report the synergetic activation of amino acids and IL1 as a coating material for lipase.Amino acids have been used as stabilizers of enzymes during the purification process. For example, commercial lipase PS contains ca. 20 wt % glycine as an essential stabilizer during the preparation of the lipase protein through the lyophilization process. 5b We investigated the role of glycine and established that it worked only as a stabilizer of the enzyme and had no influence on the reactivity of lipase PS. 5b Since it was anticipated that a chiral amino acid may modify the enantioselectivity of an enzymatic reaction, we next prepared amino acidcoated lipase PS and investigated its properties in the transesterification of («)-1-phenylethanol (1a) as a model substrate in the presence of vinyl acetate as an acyl donor in the i-Pr 2 O solvent system (Figure 2). 10 As shown in Figure 2, the coating of lipase PS with amino acids neither accelerated the reaction nor modified its enantioselectivity, although coating lipase with L-asp...

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Synergetic Activation of Lipase by an Amino Acid with Alkyl–PEG Sulfate Ionic Liquid

et al. 2013

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“…Ionic liquids (IL) have shown interesting ability as phase tags for organocatalysts. [6][7][8][9][10][11][12][13][14][15] Ionic liquid tagged catalysts can be tuned to attain a required physical property, such as solubility, or compatibility with the reaction medium and thermal stability. 16 In this way improved recovery and recycling and sometimes even better catalytic activity can be attained.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and application of azolium ionic liquid tagged TADDOL catalysts

Yacob¹,

Liebscher²

2012

Arkivoc

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Ionic liquid (IL) tagged organocatalysts based on TADDOL (α,α,α',α'-tetraaryl-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol) comprising various aryl substituents tethered with triazolium and imidazolium based ionic liquids are synthesised in good yields. Investigation of these IL-tagged catalysts on hydrogen-bonding catalyzed hetero-Diels-Alder (HDA) reactions between activated dienes (such as Rawal's diene and Brassard's diene) and benzaldehyde indicated their potential and limitations for applications in organocatalysis.

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“…The FILs have shown great promise not only as alternative green solvents, but also as reagents or catalysts in organic transformations. [23][24][25][26] We have been interested in the use of functionalized ionic liquid-supported Schiff base, since Schiff base palladium(II) compounds are excellent candidates as N, O-bidentate ligands in catalysis owing to their desirable coordinating ability with palladium. In this paper, we wish to report the use of ionic liquid-supported Schiff base as the palladium (II) ligand to demonstrate their suitability in palladium-catalyzed Suzuki-Miyaura cross-coupling reactions.…”

Section: Introductionmentioning

confidence: 99%

A novel ionic liquid-supported Schiff base ligand applied in the Pd-catalyzed Suzuki–Miyaura coupling reaction

Li¹,

Li²,

Zheng³

2010

Arkivoc

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A series of novel ionic liquid-supported Schiff bases have been prepared from the condensation of aromatic aldehydes with the ionic liquid 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate. The as-prepared ionic liquid-supported salicyladehyde Schiff base L3 was further investigated as a ligand for the Pd-catalyzed Suzuki-Miyaura coupling reaction under air in ethanol solution, giving biaryls in good to excellent yields. The PdCl 2 /ligand L3 catalytic system could be reused at least 5 times without losing its activity.

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Functionalized Chiral Ionic Liquids as Highly Efficient Asymmetric Organocatalysts for Michael Addition to Nitroolefins

Abstract: Catalytic combination: By combining the advantages of organocatalysts and ionic liquids, a functionalized chiral ionic liquid such as 1 can act as a highly efficient and reusable organocatalyst for the asymmetric Michael addition reaction of ketones and aldehydes with nitroalkenes.

Cited by 443 publications

References 81 publications

Synergetic Activation of Lipase by an Amino Acid with Alkyl–PEG Sulfate Ionic Liquid

Synergetic Activation of Lipase by an Amino Acid with Alkyl–PEG Sulfate Ionic Liquid

Synthesis and application of azolium ionic liquid tagged TADDOL catalysts

A novel ionic liquid-supported Schiff base ligand applied in the Pd-catalyzed Suzuki–Miyaura coupling reaction

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