- Preparation of highly enantiopure β-amino esters by Candida antarctica lipase A
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The enantioselectivities for the reactions of aliphatic β-substituted β-amino esters [RCH(NH2)CH2CO2Et with R = Me, Et, n-Pr, i-Pr, CHEt2, cyclohexyl and Ph] with butyl butanoate in neat butyl butanoate and with 2,2,2-trifluoroethyl butanoate in diisopropyl ether were studied in the presence of Candida antarctica lipase A. Enantioselectivities ranging from good (E = 70-100) to excellent (E>100) were commonly observed, allowing gram-scale resolution of the substrates.
- Gedey, Szilvia,Liljeblad, Arto,Lazar, Laszlo,Fueloep, Ferenc,Kanerva, Liisa T.
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- Improving Catalytic Activity and Reversing Enantio-Specificity of ω-Transaminase by Semi-Rational Engineering en Route to Chiral Bulky β-Amino Esters
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The application of wild-type ω-transaminase was limited by steric hindrance towards bulky substrates, therefore improvement of the catalytic efficiency and stereoselectivity toward substrates with two bulky substituent adjacent to the carbonyl is of general interest. In this study, according to the double substrate binding pocket theory, a (S)-selective ω-transaminase from the Burkholderia vietnamiensis G4, which showed puny catalytic activity toward the β-keto esters with small steric hindrance, was engineered to accept bulky β-keto esters, which were not accessible by any wild-type enzyme. A few desired variants were obtained that exhibited activity toward bulky β-keto esters. Furthermore, a substrate-dependent shift in enantio-preference of HBV variant towards β-keto esters with linear or branched aliphatic substituents was observed. The best variant was applied to the asymmetric synthesis of aliphatic β-amino acids at semi-preparative scale with high yield and enantioselectivity. This study will improve the general understanding and inspire further engineering work for reversing enantio-specificity of ω-transaminases.
- Wang, Yingang,Feng, Jinhui,Dong, Wenyue,Chen, Xi,Yao, Peiyuan,Wu, Qiaqing,Zhu, Dunming
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p. 3396 - 3400
(2021/06/21)
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- Enantioselektive Synthese von β-Aminosaeuren - TMS-SAMP als chirales Ammoniak-Aequivalent in der azaanalogen Michael-Addition an α,β-ungesaettigte Ester
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Stichworte: Aminosaeuren * Asymmetrische Synthesen * Chirale Hilfsstoffe * Michael-Additionen
- Enders, Dieter,Wahl, Heiner,Bettray, Wolfgang
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p. 527 - 529
(2007/10/02)
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- An enantiospecific synthesis of β-amino acids
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L-Aspartic acid by regioselective modification of the α-carboxylic acid group, namely N-tosylation, anhydride formation, reduction, iodo-esterification, alkylation, and deprotection afforded a series of γ-alkyl β-aminobutyric acids of the R configuration (ee > 99%).
- Jefford,Wang
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p. 1111 - 1114
(2007/10/02)
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