Cysteine-Derived Organocatalyst in a Highly Enantioselective Intramolecular Michael Reaction

Hayashi, Yujiro; Gotoh, Hiroaki; Tamura, Tomohide; Yamaguchi, H.; Masui, Ryouhei; Shoji, Mitsuru

doi:10.1021/ja055740s

Cited by 228 publications

(60 citation statements)

References 18 publications

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“…Proline 4 must be a type II or III olefin, according to Grubbs' classification, [15] as it undergoes a selective CM with various type I terminal olefins. Nevertheless, the reported result appears quite remarkable as, to the best of our knowledge, only few examples of CM of similar bulky homoallylic substrates with alkenes have been reported, [24] including a few with electron-deficient alkenes. [25] Unfortunately, masked amino acids 10 and 13 led to unacceptably low product yields under common deprotection and N-protection reaction conditions, due to their low solubility in water and low stability under the reaction conditions (Scheme 4).…”

Section: Resultsmentioning

confidence: 96%

Straightforward Synthesis of α‐Substituted Prolines by Cross‐Metathesis

et al. 2008

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The synthesis of several α-substituted N-Boc-protected prolines has been achieved by cross metathesis (CM) of N-Bocallylproline 5 with terminal long chain alkenes and alkenes bearing hydroxy, silyloxy, ester, and O-acetylglucosamido groups. The CM occurred with good selectivity and short reaction time under microwave heating conditions, affording yields in the range of 40-92 %. Addition of Ti(OiPr) 4 as a

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Section: Resultsmentioning

confidence: 96%

Straightforward Synthesis of α‐Substituted Prolines by Cross‐Metathesis

et al. 2008

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“…The synthetic strategy is aimed at the synthesis of core intermediate (6). Because of recent reported analogues [34] Thus, sequential double alkylation of (10) afforded the bisalkylated enone (11) in 89% overall yield. Through DIBAL-H reduction and reprotection by TBS, (11) was converted to (12).…”

Section: Racemic Formmentioning

confidence: 99%

Recent Advances on Platensimycin: A Potential Antimicrobial Agent

You²

2010

CMC

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Platensimycin, an active metabolite of Streptomyces platensis, was initially discovered by a combination of RNA interferin induced gene-silencing and library screening to microbial extracts. Platensimycin selectively inhibits beta - ketoacyl-acyl carrier protein (ACP) synthase II (FabF) that is recognized as an effective broad-spectrum antibiotic against drug-resistant microorganism strains. Its novel scaffold and extraordinary antibacterial activity have drawn great attentions in recent years. So far, a number of synthetic strategies have been explored for the total synthesis of platensimycin. Moreover, many analogues have been investigated in terms of structure-activity relationships (SAR). This review provides a detailed overview of updated studies on platensimycin, focusing on various total and formal synthetic strategies, development of analogues, and the structure-activity relationships.

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“…The reaction was shown to be totally chemoselective and to afford the final products in excellent yields and enantioselectivities (Scheme 5.35). Hayashi, soon after, reported a similar approach in which a cysteine-derived prolinamide analog was used as the catalyst [62]. Córdova and coworkers, in 2007, studied the addition of different aldehydes to maleimides, catalyzed by different amines as organocatalysts [63].…”

Section: Other Reactionsmentioning

confidence: 99%

Enamines in Catalytic Enantioselective Conjugate Additions

Rios

Moyano

2010

Catalytic Asymmetric Conjugate Reactions

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The use of chiral secondary amines as asymmetric catalysts (asymmetric aminocatalysis; AA) was pioneered during the early 1970s both by Hajos and Parrish [1] and, independently, by Eder et al. [2] in their reports on the first examples of highly enantioselective, proline-catalyzed intramolecular aldol cyclizations. In spite of some subsequent significant applications of this transformation -most notably, in Woodward's asymmetric total synthesis of erythromycin [3] -the potential of AA was largely overlooked during the following three decades. Following the rediscovery of proline in 2000 as a catalyst in the intermolecular aldol reaction by List et al. [4] and, soon after, the introduction of iminium catalysis by D. W. C. MacMillan [5] (Scheme 5.1), the development of AA -and of the broader field of asymmetric organocatalysis (AO) -has been impressive. Today, AO has become a powerful and well-established synthetic tool for the enantioselective construction of chiral organic compounds [6], that complements -and, in some instances, also improves -the more traditional approaches based on metal-catalyzed reactions [7] and on biocatalysis [8].Carbon nucleophiles that contain relatively acidic methylene groups have been widely applied in direct Michael additions, whereas simple enolizable carbonyl compounds need generally to be converted into more reactive species such as enol ethers or enamines prior to their use. Since chemical transformations that avoid additional reagents, the generation of waste, and extended working times are highly desirable, a more promising, and atom-economic strategy would involve the direct addition of unmodified carbonyl compounds to Michael acceptors. Covalently bonded aminocatalysts operate through two different mechanisms, by transforming the carbonyl substrates either into activated nucleophiles (enamine intermediates), or into electrophiles (iminium intermediates). Very recently, MacMillan and coworkers have disclosed a third way of activation that takes place via cation-radical chemistry singly occupied molecular orbital (SOMO) catalysis (Scheme 5.2) [9].Catalytic Asymmetric Conjugate Reactions. Edited by Armando Córdova

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Cysteine-Derived Organocatalyst in a Highly Enantioselective Intramolecular Michael Reaction

Cited by 228 publications

References 18 publications

Straightforward Synthesis of α‐Substituted Prolines by Cross‐Metathesis

Straightforward Synthesis of α‐Substituted Prolines by Cross‐Metathesis

Recent Advances on Platensimycin: A Potential Antimicrobial Agent

Enamines in Catalytic Enantioselective Conjugate Additions

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