Ein einfacher Zugang zu (R)-α-Hydroxycarbonsäuren und (R)- 1-Amino-2-alkoholen aus (R)-Cyanhydrinen

Ziegler, Thomas; Hörsch, Brigitte; Effenberger, Franz

doi:10.1055/s-1990-26945

Cited by 148 publications

(40 citation statements)

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“…via an acid catalyzed hydrolysis from (R)-l, a-hydroxy carboxylic acids (R)-2 are obtained without any racemization in excellent yields [10]. The unprotected cyanohydrins (R)-l can be hydrogenated without racemization with LiAIH 4 to the 1,2-amino alcohols (R)-3 (see ref.…”

Section: Transformations Of the Nitrile Group Of (R)-cyanohydrinsmentioning

confidence: 99%

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(R)- and (S)-Cyanohydrins - Their Enzymatic Synthesis and Their Reactions

Effenberger

1992

Microbial Reagents in Organic Synthesis

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ABSTRACT. The known enzymes (R)-and (S)-oxynitrilase catalyze the enantioselective addition of hydrocyanic acid to aldehydes to give (R)-and (S)-cyanohydrins. The optical yields can distinctly be improved by the application of organic solvents (i.e. ethyl acetate or diisopropyl ether) instead of a waterjethanol mixture which was used previously in these reactions. For the enzyme (S)-oxynitrilase Sorghum bicolor evolved to be the best source. The optically active cyanohydrins can be transformed without any racemization by acid catalyzed hydrolysis into a-hydroxy acids and by hydrogenation with lithiumjaluminum hydride into 1,2-amino alcohols. Via addition of Grignard reagents to the O-protected cyanohydrins and follow-up hydrogenation, 1,2-amino alcohols are gained with very high diastereoselectivity. By O-sulfonylation of the (R)-and (S)-cyanohydrins optically active a-sulfonyloxy nitriles are obtained. These nitriles react with various nucleophiles by complete inversion of configuration to form various a-substituted carboxylic acid derivatives, a-azido nitriles, a-amino nitriles, aamino acids, etc. Enzyme cata1yzed preparation of (R)-cyanohydrinsE. Pfeil et al. have investigated the (R)-oxynitrilase (E.C. 4.1.2.10) catalyzed addition of hydrocyanic acid to various aldehydes to give (R)-cyanohydrins [1]. In the applied solvents, water or waterjalcohol mixtures, the normal chemical addition of HCN cannot be avoided which results in pure optical yields in most cases. All efforts to improve the optical yields in waterjalcohol solutions failed. By using organie solvents, which are not miscible with water, however, the (R)-cyanohydrins are obtained in excellent chemical and optical yields [2]. 25 S. Servi (ed.), Microbia l Reagents in Organic Synthesis,[25][26][27][28][29][30][31][32][33]

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Section: Transformations Of the Nitrile Group Of (R)-cyanohydrinsmentioning

confidence: 99%

“…The unprotected cyanohydrins (R)-l can be hydrogenated without racemization with LiAIH 4 to the 1,2-amino alcohols (R)-3 (see ref. 10). The addition of Grignard reagents to the O-protected cyanohydrins and a follow-up hydrogenation with sodium borohydride leads to the (lR,2S)-amino alcohols 4.…”

Section: Transformations Of the Nitrile Group Of (R)-cyanohydrinsmentioning

confidence: 99%

(R)- and (S)-Cyanohydrins - Their Enzymatic Synthesis and Their Reactions

Effenberger

1992

Microbial Reagents in Organic Synthesis

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“…[3,4] Different oxynitrilases produce either (S)-or (R)-a-hydroxy nitriles often with a high degree of enantioselectivity; these subsequently can be chemically or enzymatically converted in enantioconservative reaction steps to chiral a-hydroxy acids. [5,6] The second established biotransformation process applies the (reversible) chemical addition of HCN to aldehydes and ketones (resulting in racemic hydroxy nitriles) combined with enantioselective nitrilases. Unfortunately, only very few truly enantiospecific nitrilases are currently known and these nitrilases have only been shown to convert (substituted) mandelonitrile(s) to (R)-mandelic acid(s).…”

Section: Introductionmentioning

confidence: 99%

Construction of Recombinant Escherichia coli Catalysts which Simultaneously Express an (S)‐Oxynitrilase and Different Nitrilase Variants for the Synthesis of (S)‐Mandelic Acid and (S)‐Mandelic Amide from Benzaldehyde and Cyanide

Sosedov¹,

Matzer²,

Bürger³

et al. 2009

Adv Synth Catal

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Recombinant Escherichia coli strains were constructed which simultaneously expressed the genes encoding the (S)-oxynitrilase from cassava (Manihot esculenta) together with the wild-type or a mutant variant of the arylacetonitrilase from Pseudomonas fluorescens EBC191 in a single organism under the control of a rhamnose-inducible promoter. The whole cell catalysts obtained converted benzaldehyde and potassium cyanide in aqueous media at pH 5.2 mainly to (S)-mandelic acid and/or (S)-mandelic amide and synthesized only low amounts of the corresponding (R)-enantiomers. The conversion of benzaldehyde and potassium cyanide (KCN) by a whole-cell catalyst simultaneously expressing the (S)-oxynitrilase and the wild-type nitrilase resulted in a ratio of (S)-mandelic acid to (S)-mandelic amide of about 4:3. This could be explained by the strong nitrile hydratase activity of the wild-type nitrilase with (S)-mandelonitrile as substrate. The relative proportion of (S)-mandelic amide formed in this system was significantly increased by coexpressing the (S)-oxynitrilase with a carboxy-terminally truncated variant of the nitrilase. This whole-cell catalyst converted benzaldehyde and KCN to mandelic amide and mandelic acid in a ratio of about 9:1. The ee of the (S)-mandelic amide formed was calculated to be > 95%.

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“…1 Upon reaction, cyanohydrins or cyano trimethylsilyl ethers can be transformed into the corresponding α-hydroxyacids, 2 α-hydroxyketones, 3 α-amino acids, 4 and β-amino alcohols, 5 which are not only important building blocks in the synthesis of natural products but also in the field of biology and pharmaceuticals.…”

Section: Introductionmentioning

confidence: 99%

Lanthanide dithiocarbamate complexes: efficient catalysts for the cyanosilylation of aldehydes

Vale¹,

Faustino²,

Menezes³

et al. 2006

J. Braz. Chem. Soc.

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Uma nova classe de complexos ditiocarbamato de lantanídeo foi usada para promover a cianosililação de aldeídos com elevados rendimentos à temperatura ambiente. Esta é a primeira aplicação de ditiocarbamato de lantanídeo atuando como ácido de Lewis.A new class of lanthanide dithiocarbamate complexes was used to promote the cyanosilylation of aldehydes at high yields at room temperature. This represents the first application of lanthanide dithiocarbamate acting as Lewis acid.

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Ein einfacher Zugang zu (R)-α-Hydroxycarbonsäuren und (R)- 1-Amino-2-alkoholen aus (R)-Cyanhydrinen

Cited by 148 publications

References 0 publications

(R)- and (S)-Cyanohydrins - Their Enzymatic Synthesis and Their Reactions

(R)- and (S)-Cyanohydrins - Their Enzymatic Synthesis and Their Reactions

Construction of Recombinant Escherichia coli Catalysts which Simultaneously Express an (S)‐Oxynitrilase and Different Nitrilase Variants for the Synthesis of (S)‐Mandelic Acid and (S)‐Mandelic Amide from Benzaldehyde and Cyanide

Lanthanide dithiocarbamate complexes: efficient catalysts for the cyanosilylation of aldehydes

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