- Chemoenzymatic Synthesis of Methyl (6S)-(-)-6,8-Dihydroxyoctanoate: A Precursor to (R)-(+)-α-Lipoic Acid
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A short synthetic sequence for the preparation of methyl (6S)-(-)-6,8-dihydroxyoctanoate, the precursor to (R)-(+)-α-lipoic acid is described starting from (2S)-(+)-2-(tetrahydro-2-furyl)ethanol.
- Laxmi, Y. R. Santosh,Iyengar, D. S.
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- A Novel Enantiospecific Synthesis of (S)-(-)-Methyl 6,8-Dihydroxyoctanoate, a Precursor of (R)-(+)-α-Lipoic Acid
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(S)-(-)-Methyl 6,8-dihydroxyoctanoate has been synthesised, with stereocontrolled reduction of methyl 8,8-dimethyl-6-oxo-octanoate using immobilised Bakers yeast as a key step.
- Dasaradhi, L.,Fadnavis, N. W.,Bhalerao, U. T.
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- A short enantioselective formal synthesis of methyl (S)-(-)-6,8-dihydroxyoctanoate: A key intermediate for the synthesis of R-(+)-α-lipoic acid
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A short enantioselective formal synthesis of methyl (S)-(-)-6,8-dihydroxyoctanoate starting from readily available 2-nitrocyclohexanone using a novel retro-Henry reaction is described.
- Bezbarua, Maitreyee,Saikia, Anil K.,Barua, Nabin C.,Kalita, Dipak,Ghosh, Anil C.
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- Chirality induction and chiron approaches to enantioselective total synthesis of α-lipoic acid
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Abstract An efficient, short and convenient asymmetric synthesis of (R)-(+)-lipoic acid in seven steps from chiral hydroxy aldehyde with 32.5% overall yield is described. Synthesis of S and R enantiomers of α-lipoic acid from cis-1,4-butene diol derived chiral lactone is reported with 34 % overall yield. The present synthesis involves use of simple reaction conditions making it a convenient synthesis.
- Chavan, Subhash P.,Pawar, Kailash P.,Praveen, Ch.,Patil, Niteen B.
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p. 4213 - 4218
(2015/06/02)
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- An enantioselective formal synthesis of (+)-(R)-α-lipoic acid by an L-proline-catalyzed aldol reaction
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An efficient, highly stereocontrolled formal synthesis of (+)-(R)-α-lipoic acid was achieved, which utilizes an L-proline-catalyzed highly enantio- and diastereoselective cross-aldol reaction as the key step. Georg Thieme Verlag Stuttgart.
- Zhang, Shilei,Chen, Xiaobei,Zhang, Jiangang,Wang, Wei,Duan, Wenhu
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p. 383 - 386
(2008/09/20)
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- An efficient, highly enantioenriched route to L-carnitine and α-lipoic acid via hydrolytic kinetic resolution
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A general and practical approach for the synthesis of C-4 chiral building blocks using Jacobsen's hydrolytic kinetic resolution technique to resolve terminal epoxides and diols in high enantiomeric excess and excellent yields is described. The utilization of these building blocks for the synthesis of biologically important natural products L-carnitine and α-lipoic acid is illustrated. Georg Thieme Verlag Stuttgart.
- Bose, D. Subhas,Fatima, Liyakat,Rajender, Salla
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p. 1863 - 1867
(2008/01/27)
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- Method for producing enantiomer-free 6,8 dihydroxy octanoic acid esters by means of asymmetric, catalytic hydrogenation
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The invention relates to a process for the preparation of compounds of the general formula I in which R1 represents a C1-C20-alkyl group, a C3-C12-cycloalkyl group, a C7-C12-aralkyl group or a mono- or bi-nuclear aryl group, in which a ketone of formula II wherein R1 is as defined above, is subjected to asymmetric hydrogenation.
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- Preparation of dihydroxycarboxylic esters in the absence of solvents
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A description is given of a process for preparing dihydroxycarboxylic esters and of an overall process for preparing R-(+)-α-lipoic acid.
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- Asymmetric dihydroxylation and hydrogenation approaches to the enantioselective synthesis of R-(+)-α-lipoic acid
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The asymmetric synthesis of methyl (S)-6,8-dihydroxyoctanoate (5) and (S)-6,8-dimethylsulfonyloxyoctane-1-carboxylic acid (13), key precursors to R-(+)-α-lipoic acid (6) is described using OsO4-catalyzed asymmetric dihydroxylation and Ru-catalyzed asymmetric hydrogenation, respectively, as the key steps in the reaction sequence. These methods lead to an efficient formal synthesis of R-(+)-α-lipoic acid in 90% ee.
- Upadhya,Nikalje,Sudalai
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p. 4891 - 4893
(2007/10/03)
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- A short and productive synthesis of (R)-α-Lipoic acid
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(R)-α-Lipoic acid is synthesized in seven steps from the base chemicals methyl acetoacetate or Meldrum's acid and monomethyl adipate. The key steps are the introduction of the stereogenic center by fermentative or homogeneously catalyzed hydrogenation of 3-oxooctanedioic acid diester to (3S)-3-hydroxyoctanedioic acid diester and its regioselective reduction to (6S)-6,8-dihydroxyoctanoic acid ester. The overall yield of (R)-α-lipoic acid, starting from 3-oxooctanedioic acid diester, is 40%.
- Bringmann, Gerhard,Herzberg, Daniela,Adam, Geo,Balkenhohl, Friedhelm,Paust, Joachim
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p. 655 - 661
(2007/10/03)
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- Synthesis of methyl (S)-(-)-6,8-dihydroxyoctanoate as a precursor of (R)-(+)-α-lipoic acid
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The synthesis of methyl (S)-(-)-6,8-dihydroxyoctanoate as a precursor of (R)-(+)-α-lipoic acid was accomplished by using methyl (S)-(-)-(2-oxocyclohexyl)acetate, which had been obtained from baker's yeast reduction, as a chiral starting material.
- Ganaha, Makoto,Yamauchi, Satoshi,Kinoshita, Yoshiro
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p. 2025 - 2027
(2007/10/03)
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- The synthesis of (R)-(+)-lipoic acid using a monooxygenase-catalysed biotransformation as the key step
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2-(2-Acetoxyethyl)cyclohexanone (4) was converted into the lactone (-)-(5) regio- and enantioselectively using 2-oxo-Δ3-4,5,5-trimethylcyclopentenyl acetyl-CoA monooxygenase, an NADPH-dependent Baeyer-Villiger monooxygenase from camphor grown Pseudomonas putida NCIMB 10007. The lactone (-)-(5) was converted into (R)-(+)-lipoic acid in six steps. In contrast cyclopentanone monooxygenase, an NADPH-dependent Baeyer-Villiger monooxygenase from cyclopentanol-grown Pseudomonas sp. NCIMB 9872 selectively oxidized the (S)-enantiomer of the ketone (4) giving better access to optically enriched, naturally occurring lipoic acid.
- Adger, Brian,Bes, M. Teresa,Grogan, Gideon,McCague, Raymond,Pedragosa-Moreau, Sandrine,Roberts, Stanley M.,Villa, Raffaella,Wan, Peter W. H.,Willetts, Andrew J.
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p. 253 - 261
(2007/10/03)
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- Preparation of (6s)-6,8-dihydroxyoctanoic esters
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(6S)-6,8-Dihydroxyoctanoic esters I STR1 (R1 =alkyl, cycloalkyl, aralkyl or aryl), are prepared by reducing a (3S)-3-hydroxyoctanedioic diester II STR2 (R2 =an R1 radical group) with a complex hydride and are mainly used as intermediates for synthesizing compounds of the type of liponic acid.
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- Application of Enzymic Baeyer-Villiger Oxidations of 2-Substituted Cycloalkanones to the Total Synthesis of (R)-(+)-Lipoic Acid
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Oxidation of ketones 1a-h using a monooxygenase from Pseudomonas putida NCIMB 10007 gave the lactones 2a-h in optically active form: lactone 2h was converted into (R)-(+)-lipoic acid 9.
- Adger, Brian,Bes, M. Teresa,Grogan, Gideon,McCague, Ray,Pedragosa-Moreau, Sandrine,et al.
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p. 1563 - 1564
(2007/10/02)
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- SYNTHESES OF α-(R)-AND α-(S)-LIPOIC ACID FROM (S)-MALIC ACID
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(S)-Malic acid has been converted into α-(R)-and α-(S)-lipoic acid via (R)-and (S)-(2-phenylmethoxyethyl)oxirane .The (R)-oxirane (2a) was cleaved with but-3-enylmagnesium bromide (cuprate catalysis) to give (S)-1-(phenylmethoxy)oct-7-en-3-ol (4a).This was converted into methyl (S)-6,8-dihydroxyoctanoate (5a), the di-O-methanesulphonate (6a) of which was treated with sodium sulphide and sulphur in dimethylformamide to yield methyl α-(R)-lipoate (7a), that was saponified to α-(R)-lipoic acid (1a).The (S)-oxirane (2b) was similarly converted into α-(S)-lipoic acid (1b).
- Brookes, Michael H.,Golding, Bernard T.,Hudson, Alan T.
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