Current Progress in the Acetate/Methyl Ketone Aldol Reaction

Kimball, David B.; Silks, Louis A.

doi:10.2174/138527206778521268

Cited by 18 publications

(7 citation statements)

References 77 publications

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“…[10][11][12][13] Since CILs used as catalyst in aldol reaction by Luo et al 14 in 2007, many CILs were developed as catalysts for asymmetric reactions. However, in asymmetric reactions where CILs cannot be applied as catalysts, using CILs as the solvent to investigate the chiral inducing capabilities has rarely been reported.…”

Section: Introductionmentioning

confidence: 99%

Novel chiral ionic liquid (CIL) assisted selectivity enhancement to (L)-proline catalyzed asymmetric aldol reactions

Zhang¹,

Zhang²,

Luo³

et al. 2011

J. Braz. Chem. Soc.

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Melhoras significativas nos rendimentos químicos (até 88%), estereosseletividades (> 99:1) e excessos enantioméricos (até 98%) foram observadas em reações aldólicas assimétricas catalisadas por (L)-prolina, quando líquidos iônicos quirais baseados em prolina (CILs) foram usados como aditivos. Diferentes proporções de DMSO/H 2 O como solvente, e líquidos iônicos quirais (CILs) com cátions quirais com diferentes comprimentos de cadeia, foram investigados.A significant improvement of the chemical yields (up to 88%), stereoselectivity (> 99:1) and enantiomeric excesses (up to 98%) of (L)-proline catalyzed direct asymmetric aldol reaction was found when proline based chiral ionic liquids (CILs) were added as additives. Different ratios of DMSO/H 2 O as solvent and chiral ionic liquids (CILs) with chiral cations of different chain length were investigated. Keywords: aldol reaction, asymmetric synthesis, chiral ionic liquids, chiral additive IntroductionRoom temperature ionic liquids (RTILs) including chiral ionic liquids (CILs) have received growing attentions both from theoretical research and actual productions due to their tuneable features for various chemical tasks and their advantages as homogeneous support, reaction media, etc.1,2 Since the first example of chiral ionic liquid reported by Howarth et al. 3 in 1997, a large number of CILs bearing chiral cations, anions or seldom both were reported by other groups. 4,5 Previous studies have shown that in many asymmetric reactions the use of CILs as reaction media or catalyst can enhance the yield and/or selectivity significantly. [6][7][8] As most of the asymmetric reactions were carried out using metal/chiral catalysts as chiral sources, which are relatively expensive or environmental unfriendly, searching for a catalyst which is easy to obtain and environmentally benign for the asymmetric reactions is of great significance. In our previous work, a series of (L)-proline based CILs were proved to have the potential to provide a strong chiral environment by 19 F NMR study. 9 In this article, a series of reactions were carried out to investigate the catalytic properties of these (L)-proline based CILs, and very high chiral selectivity was obtained.Aldol reaction has been a typical asymmetric reaction used in the search of efficient asymmetric catalyst, especially for environmental friendly and metal-free organic catalyst. [10][11][12][13] Since CILs used as catalyst in aldol reaction by Luo et al. 14 in 2007, many CILs were developed as catalysts for asymmetric reactions. However, in asymmetric reactions where CILs cannot be applied as catalysts, using CILs as the solvent to investigate the chiral inducing capabilities has rarely been reported. Here we chose the asymmetric aldol reactions as our initial focus to examine the applications of CILs in asymmetric reactions. (L)-Proline and its structural analogs were found to be good catalyst for aldol reaction, [15][16][17][18][19] and (L)-proline combined with ILs were also proved to be an efficient catalytic ...

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Section: Introductionmentioning

confidence: 99%

Novel chiral ionic liquid (CIL) assisted selectivity enhancement to (L)-proline catalyzed asymmetric aldol reactions

Zhang¹,

Zhang²,

Luo³

et al. 2011

J. Braz. Chem. Soc.

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“…Numerous investigations revealed that the orientation of the reaction is in close relationship with the composition of the reactants and the experimental condition. In most cases, this type of reaction could provides an ,-unsaturated ketone via aldol condensation (the Claisen-Schmidt condensation) [1][2][3][4][5][6][7][8] or a -hydroxyketone via direct aldol addition [9][10][11][12][13] (Scheme 1). The reaction could also produces linear 1,5-diones [14][15][16], triones [17], or cyclohexane derivatives [18][19][20][21][22] via the multimolecular reaction.…”

Section: Introductionmentioning

confidence: 99%

New observation on a class of old reactions: Chemoselectivity for the solvent-free reaction of aromatic aldehydes with alkylketones catalyzed by a double-component inorganic base system

Zhang

Xin-xiang

et al. 2010

Sci. China Chem.

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Solvent-free reactions of aromatic aldehydes with three representative ketones, including acetophenone, acetone and cyclohexanone, have been examined under the catalysis of a low-cost inorganic base system consisting of NaOH and K 2 CO 3 . It was found that the chemoselectivity of the reactions is in close relationship with the composition of the reactants and the doublecomponent catalyst. Under the optimized experimental conditions, 1,2,3,4,5-pentasubstituted cyclohexanols, ,-unsaturated ketones and Claisen-Schmidt bicondensation products were obtained in high yields. Two Kostanecki's triketones were separated, The composition and structure were affirmed by X-ray crystallographic analysis. solvent-free reaction, solid base mixture catalysis, chemoselectivity, aldehyde-ketone reaction

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“…Many protocols have been established in which specially designed catalysts achieve excellent yields and selectivities [10][11][12]. Proline and proline derivatives were found as the most promising catalysts for aldol reactions [13,14].…”

Section: Introductionmentioning

confidence: 99%

Ionic liquid mediated recyclable sulphonimide based organocatalysis for aldol reaction

Srivastava

2010

Open Chemistry

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Current Progress in the Acetate/Methyl Ketone Aldol Reaction

Cited by 18 publications

References 77 publications

Novel chiral ionic liquid (CIL) assisted selectivity enhancement to (L)-proline catalyzed asymmetric aldol reactions

Novel chiral ionic liquid (CIL) assisted selectivity enhancement to (L)-proline catalyzed asymmetric aldol reactions

New observation on a class of old reactions: Chemoselectivity for the solvent-free reaction of aromatic aldehydes with alkylketones catalyzed by a double-component inorganic base system

Ionic liquid mediated recyclable sulphonimide based organocatalysis for aldol reaction

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