(S)-Pyrrolidine sulfonamide catalyzed asymmetric direct aldol reactions of aryl methyl ketones with aryl aldehydes

Mei, Kui; Zhang, Shilei; He, Songtao; Li, Ping; Jin, Mei; Xue, Fei; Luo, Guangshun; Zhang, Haoyi; Song, Lirong; Duan, Wenhu; Wang, Wei

doi:10.1016/j.tetlet.2008.02.164

Cited by 71 publications

(15 citation statements)

References 73 publications

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“…Hence, sulfonamide (260a) (10 mol%; Figure 3.11) was very efficient in the aldol reaction between aryl methyl ketones and aromatic aldehydes in DMSO as solvent at 25 • C in the presence of 1 equiv of water as additive, yielding the corresponding aldol products with good results (18-91% yield, 71-91% ee). Lower yields were encountered in reaction between acetophenone and benzaldehyde [309]. Recyclable fluoro-sulfonamide 260b (10 mol%) was used as catalyst in water at 0 • C for the reaction between acyclic and cyclic ketones (5 equiv) with aromatic aldehydes affording products 54 (73-93% yield, 0-90% de, and 70-97% ee).…”

Section: Ketones As Source Of Nucleophilementioning

confidence: 99%

Organocatalyzed Aldol Reactions

Guillena¹

2013

Modern Methods in Stereoselective Aldol Reactions

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The use of catalytic enantioselective methods to perform an aldol reaction provides a direct entry for the synthesis of chiral compounds and is probably the most attractive way to achieve this goal with high control of the chemo-, regio-, diastereo-, and enantioselectivity. The application of biochemical methods based on enzyme aldolases or antibodies, which are discussed in other chapters, avoid the use of preformed enolates or their equivalents for enhancing the global atom efficiency of the process [1] for which the narrow substrate scope is a major drawback. The discovery of methodologies to carry out the enantioselective direct aldol reaction [2] has eluded the production of stoichiometric by-products increasing the substrate scope. This task could be accomplished by using small molecules as catalysts, such as metal complexes (which are covered along this book) and organic molecules, also known as organocatalysts [3]. The growth of this last research area and the direct aldol reaction are closely linked [4], with the report on the use of (S)-proline as catalyst for the intermolecular aldol [5] definitely being the push for the development of the organocatalytic methods as a competitive methodology for the synthesis of chiral compounds.In a strict sense, an organocatalyzed reaction is a process in which all the involved reagents and catalysis are purely organic compounds of low-molecular weight, excluding boron-and silicon-containing derivatives. However, in some cases, the presence of a silyl group only plays a steric role and therefore can also be considered as an organocatalyzed process. Also, if the organocatalyst involved in a reaction is immobilized in a polymer, a dendrimer, or even an inorganic material that serves only as a support to facilitate its recovery [6], it could still be considered as an organocatalyst, although those types of derivatives have been scarcely used in the natural product synthesis and therefore will be excluded from this chapter. Therefore, a comprehensive overview of the direct aldol reaction [7], emphasizing the reactivity, scope, selectivity, and limitations of the methodology and giving several examples of their application to the synthesis of biologically active compounds, is discussed in this chapter.

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Section: Ketones As Source Of Nucleophilementioning

confidence: 99%

Organocatalyzed Aldol Reactions

Guillena¹

2013

Modern Methods in Stereoselective Aldol Reactions

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“…Compound 21 has been applied to an aldol reaction of ketones with 1,2-diketones, [31] whilst very similar compounds (SO2Ph in place of Ts) have been prepared via ring opening of a sulfonated aziridine ring and applied to the organocatalysis of aldol reactions. [32] Several derivatives of C2-symmetric DPEN and of trans 1,2-diaminocyclohexane, bearing the combination of prolinamide and carbamate/thiocarbamate, [33][34][35][36][37] or dialkyl substituents, [38] have been reported in organocatalytic asymmetric transformations. We first attempted acetophenone reduction using 20 and 21 with a 5:2 mixture of FA/TEA as the solvent and hydrogen donor (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Application of Proline‐Functionalised 1,2‐Diphenylethane‐1,2‐diamine (DPEN) in Asymmetric Transfer Hydrogenation of Ketones

Manville

Docherty²,

Padda³

et al. 2011

Eur J Org Chem

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“…Prolonged heating resulted in the further reduction of 1a-5a (entries 9-10). Other substituted nitrochalcones 7b-d also afforded quinoline Noxides 1 in good yields, however, small amount of starting chalcones 7b-d were still remained unreacted (entries [11][12][13].…”

Section: Resultsmentioning

confidence: 99%

Chemoselective synthesis of quinoline N‐oxides from 3‐(2‐nitrophenyl)‐3‐hydroxypropanones

Okuma

Seto

Nagahora

et al. 2010

Journal of Heterocyclic Chem

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The reaction of 3-(2-nitrophenyl)-3-hydroxypropanones with Zn/NH 4 Cl gave the corresponding quinoline N-oxides in 80-90% yields. The reaction initiated the reduction of nitro group to afford the corresponding hydroxylamine, which intramolecularly condensed and followed by dehydration to give quinoline N-oxide. Although treatment of 2-nitrochalcone with Zn/NH 4 Cl in EtOH/H 2 O resulted in the formation of quinoline N-oxide in low yield, the reaction of 2-nitrochalcone with Sn/NH 4 Cl in refluxing EtOH/H 2 O afforded quinoline N-oxide in 80% yield.

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(S)-Pyrrolidine sulfonamide catalyzed asymmetric direct aldol reactions of aryl methyl ketones with aryl aldehydes

Cited by 71 publications

References 73 publications

Organocatalyzed Aldol Reactions

Organocatalyzed Aldol Reactions

Application of Proline‐Functionalised 1,2‐Diphenylethane‐1,2‐diamine (DPEN) in Asymmetric Transfer Hydrogenation of Ketones

Chemoselective synthesis of quinoline N‐oxides from 3‐(2‐nitrophenyl)‐3‐hydroxypropanones

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