- Syntheses of (2S,3R)- and (2S,3R)2H>- 3-Methylaspartic acid: Slow Substrates for a syn-Elimination Reaction catalysed by Methylaspartase.
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Methylaspartase catalyses the slow syn-elimination of ammonia from the (2S,3R)--diastereomer of the natural substrate, (2S,3S)-3-methylaspartic acid, to give mesaconic acid.To provide material of sufficient stereochemical purity to probe the mechanism of the reaction, two synthetic routes to (2S,3R)- and (2S,3R)2H>- 3-methylaspartic acid were devised.The use of these (2S,3R)-3-methylaspartic acids revealed that the enzymic reaction does not involve C-3 epimerisation followed by normal anti-elimination, ruling-out the possibility of a carbanion intermediate.Conversely, the substrate displayed very large primary deuterium isotope effects indicating rate-limiting C-H bond cleavage.
- Archer, Catherine H.,Thomas, Neil R.,Gani, David
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- Indium-mediated allylation and Reformatsky reaction on glyoxylic oximes under ultrasound irradiation
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A novel and more convenient method for the indium-promoted allylation of glyoxylic oximes based on the use of ultrasonic waves is reported. A similar procedure was used to develop the first example reported in the literature of an indium-mediated Reformatsky reaction on oxime ethers.
- Soengas, Raquel G.,Estévez, Amalia M.
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experimental part
p. 916 - 920
(2012/06/04)
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- Organocatalytic synthesis of β-alkylaspartates via β-lactone ring opening
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(Chemical Equation Presented) Cinchona alkaloid-catalyzed reaction of ethyl glyoxylate with substituted ketenes, formed in situ, gives disubstituted β-lactones in moderate yield and high enantiomeric excess. Subsequent azide ring opening, reduction, and e
- Armstrong, Alan,Geldart, Stephen P.,Jenner, Chloe R.,Scutt, James N.
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p. 8091 - 8094
(2008/02/13)
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- SYNTHESIS AND ABSOLUTE STEREOCHEMISTRY OF SERRICORNIN
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The absolute stereochemistry of serricornin (4,6-dimethyl-7-hydroxy-3-nonanone) was established as 4S, 6S, 7S by synthesizing both (4S, 6S, 7S)-isomer and its antipode.Only the natural enantiomer was bioactive.by
- Mori, Kenji,Nomi, Hiroko,Chuman, Tatsuji,Kohno, Masahiro,Kato, Kunio,Noguchi, Masao
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p. 3705 - 3712
(2007/10/02)
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