Efficient Preparation of Optically Pure Wieland-Miescher Ketone and Confirmation of Its Absolute Stereochemistry by the CD Exciton Chirality Method

Harada, Nobuyuki; Sugioka, T.; Uda, Hisashi; Kuriki, Takeo

doi:10.1055/s-1990-26786

Cited by 64 publications

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“…After addition of water, the mixture was extracted with ethyl acetate, and the organic layers were washed with brine, dried with anhydrous MgSO 4 , and evaporated under reduced pressure. The residue obtained was dissolved in THF (0.1 ml), and the solution was stirred with TBAF in THF (1.0 M, 0.1 ml) at room temperature for 17 h. The solvent was evaporated under reduced pressure, and the residue was purified by short column chromatography on silica gel (hexane/EtOAc = 1:2) yielding diol (1R,6R,8aR)-(À)-7 (0.0092 g, 85%) as colorless prisms, which was identical with the authentic sample: 9 [a] D 26 À54.1 (c 1.01, EtOH); lit. 9 [a] D À50.3 (c 1.025, EtOH).…”

Section: Recovery Of Enantiopure Diol (1r6r8ar )-(à)-7mentioning

confidence: 80%

“…Ketone (F)-4 was converted to 6,6-ethylene acetal, 12 which was then reduced with NaBH 4 , yielding alcohol (F)-6. Ketone (F)-4 was reduced with LiAlH 4 to give diol (F)-7, 9 which was converted to 6-tert-butyldimethylsilyl (TBDMS) ether (F)-8 and 6-tert-butyldiphenylsilyl (TBDPS) ether (F)-9 as described herein.…”

Section: Synthesismentioning

confidence: 99%

“…70% ee), 8 which was then enantiomerically enriched by repeated recrystallizations, affording enantiopure W-M ketone. 9 On the other hand, methods of kinetic resolution of W-M ketone (F)-4 or its derivatives using yeast or enzyme have been recently developed; 10 for example, racemic ketone (F)-4 was treated with a yeast strain yielding (8aR)-4 (74%, 34.8% ee) and alcohol (1S,8aS )-5 (26%, 97.8% ee, 96.2% de). 10a It remains difficult to obtain enantiopure W-M ketone 4 efficiently.…”

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confidence: 99%

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Preparation of enantiopure Wieland–Miescher ketone and derivatives by the MαNP acid method. Substituent effect on the HPLC separation

Kasai¹,

Shimanuki²,

Kuwahara³

et al. 2006

Chirality

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Enantiopure Wieland-Miescher ketone (4, W-M ketone) and derivatives were prepared by the enantioresolution with 2-methoxy-2-(1-naphthyl)propionic acid (MalphaNP acid 1). Various racemic derivatives of 4 were esterified with acid (S)-(+)-1 yielding diastereomeric MalphaNP esters, which were separated by HPLC on silica gel. It was clarified that the HPLC separation of diastereomers depended on the substituent of the derivatives, leading to the working hypothesis that MalphaNP acid esters of alcohols with less polar and more bulky aliphatic substituents are more effectively separated. The best separation was obtained in the case of tert-butyldimethylsilyl (TBDMS) ether derivative (12a/12b): separation factor alpha=1.80, and resolution factor, Rs=1.30. The (1)H NMR spectra of separated MalphaNP esters showed anomalously large magnetic anisotropy effects, from which their absolute configurations were determined. Solvolysis or reduction of the separated MalphaNP esters yielded alcohols, which were converted to enantiopure W-M ketones 4. The results thus provided another route for preparation of enantiopure ketones (8aR)-(-)-4 and (8aS)-(+)-4.

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Section: Recovery Of Enantiopure Diol (1r6r8ar )-(à)-7mentioning

confidence: 80%

Section: Synthesismentioning

confidence: 99%

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confidence: 99%

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Preparation of enantiopure Wieland–Miescher ketone and derivatives by the MαNP acid method. Substituent effect on the HPLC separation

Kasai¹,

Shimanuki²,

Kuwahara³

et al. 2006

Chirality

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“…Para o caso da nitro-olefina cíclica 1-nitro-ciclo-hexeno, o único produto observado foi o cis-1-nitro-2-(feniltio)-ciclo-hexano em 70% de rendimento. É interessante apontar a síntese da tricetona (6), sem catálise básica, a partir da adição conjugada de 2-metil-1,3-ciclopentanona à metilvinilcetona (Esquema 33) [59][60][61] . O composto obtido pode ser empregado na síntese de anéis fundidos.…”

Section: Esquema 32 Adição De Michael De Tiofenol a (E)-nitro Oleofiunclassified

Reações orgânicas em meio aquoso

Silva

Jones

2001

Quím. Nova

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Recebido em 21/7/00; aceito em 13/12/00 ORGANIC REACTIONS IN AQUEOUS MEDIA. The use of water as solvent in organic reactions has been uncommon for several reasons, among them the low solubility of the reactants, the incompatibility of the intermediates with water, and the competition between the desired reaction and hydrolysis. Breslow in 1980, demonstrated that the hydrophobic effect accelerates Diels-Alder reactions and gives a high endo/exo selectivity. Since then, many other reactions were studied in this medium, and below we show the principal results. Besides the academic interest, human and economic aspects are included in this study. Water as a solvent minimizes environmental impact, costs and increases operational safety.Keywords: water; organic reactions; hydrophobic effect. Quim. Nova, Vol. 24, No. 5, 646-657, 2001. Revisão INTRODUÇÃOA utilização de água como solvente costumava ser descartada dos estudos de reações orgânicas por diversas razões, entre elas, a insolubilidade dos reagentes, a incompatibilidade dos intermediários com a água e a competição das reações desejadas com processos de hidrólise dos reagentes 1,2 . No entanto, um dos principais problemas na indústria química está relacionado com a utilização de solventes orgânicos em seus processos. Sua manufatura, transporte, estoque, manuseio e descarte são aspectos que demandam muito cuidado e dinheiro. Por estes motivos, a substituição de solventes orgânicos como meio reacional por água é de grande interesse no que diz respeito a síntese orgânica, visto que minimiza o impacto ambiental, além de ter mais baixo custo e apresentar menor periculosidade operacional.Em adição aos aspectos econômicos e humanos, a água apresenta muitas propriedades físico-químicas que podem ser úteis nas reações, como a alta polaridade, à capacidade de solvatar íons, formar ligações hidrogênio, ser um líquido estruturado, e agregar moléculas apolares dissolvidas (efeito hidrofóbico) 1,3,4,5 . ESTRUTURA DA ÁGUAUm solvente não pode ser considerado apenas por suas características contínuas macroscópicas, ou seja, constantes físicas como densidade, constante dielétrica, índice de refração, entre outras, mas também devem ser levadas em consideração características descontínuas, que consistem nas interações entre moléculas de solventes. De acordo com a extensão destas interações, os líquidos podem ser divididos em dois grupos: não-estruturados e estruturados ou regulares. No primeiro, as molé-culas permanecem juntas por forças fracas não-direcionais de van der Waals. No segundo grupo, onde a água se encaixa, as moléculas permanecem unidas por forças fortes e direcionais, como as ligações hidrogênio. Nos líquidos estruturados, as moléculas não preenchem todo o espaço de forma eficaz, e como conseqüência sua estrutura possui cavidades 1,3 . A estrutura da água e sua importância ainda são objeto de muitos trabalhos na literatura. De forma geral, a água líquida é representada tanto por regiões ligadas de maneira ordenada, quanto por regiões ligadas de forma aleatória por ligaç...

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“…28 In some cases, the Michael additions may be carried out without any type of catalysis. [29][30][31][32] Moreover, it is interesting to point out that in the applications of these aqueous methodologies, many nucleophile types can be used, including organometallic regents. [33][34][35][36] In our research, we have analyzed some studies of this type of reaction in water catalyzed by bases without phase transfer agents.…”

Section: Introductionmentioning

confidence: 99%

Michael additions of thiocompounds to α, β-unsaturated carbonyl compounds in aqueous media: stereoselectivity with unambiguous characterization by NMR

Aparecida¹,

Almeida²,

Pereira³

et al. 2008

J. Braz. Chem. Soc.

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Efficient Preparation of Optically Pure Wieland-Miescher Ketone and Confirmation of Its Absolute Stereochemistry by the CD Exciton Chirality Method

Cited by 64 publications

References 0 publications

Preparation of enantiopure Wieland–Miescher ketone and derivatives by the MαNP acid method. Substituent effect on the HPLC separation

Preparation of enantiopure Wieland–Miescher ketone and derivatives by the MαNP acid method. Substituent effect on the HPLC separation

Reações orgânicas em meio aquoso

Michael additions of thiocompounds to α, β-unsaturated carbonyl compounds in aqueous media: stereoselectivity with unambiguous characterization by NMR

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