34047-84-2Relevant academic research and scientific papers
ASYMMETRISCHE KATALYSEN. XXX. ENANTIOSELEKTIVE HYDRIERUNG VON CROTONSAEUREDERIVATEN MIT RHODIUM-PHOSPHIN-KATALYSATOREN
Brunner, Henri,Knott, Alfons,Kunz, Manfred,Thalhammer, Elisabeth
, p. 55 - 62 (1986)
The Z- and E-isomers of the α-N-benzoylamino-2-butenoic acid methyl ester, the E/Z mixtures of α-N-benzoylamino-2-butenoic acid, and the Z-form of α-N-acetylamino-2-butenoic acid were hydrogenated enantioselectively.The hydrogenation products are derivatives of α-aminobutyric acid, which can be reduced to aminobutanol, the optically active component of the antituberculosis drug (+)-ethambutol.In situ catalysts consisting of 2 and the optically active phosphine ligands (+)- and (-)-Norphos, (+)-Prophos, (-)-Chiraphos, (-)-BPPFA, (-)-Diop, and (+)- and (-)-CpMn(CO)2diop were used.The best results were obtained with the substrate (Z)-α-acetylamino-2-butenoic acid and the catalyst 2/(-)-Norphos with 91.5percent e.e.
Preparation method of chiral alpha-amino acid
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, (2016/10/08)
The invention discloses a preparation method of chiral alpha-amino acid. Initial raw materials comprising aldehyde and N-acryl substituted glycine undergo Erlenmeyer-Plochl cyclization, hydrolysis or alcoholysis, asymmetric catalytic hydrogenation and acid hydrolysis to obtain the chiral alpha-amino acid compound. The method adopting the above synthesis route has the advantages of mild reaction conditions, simple technological operation, safe and stable production, realization of high yield, good chemical purity and good optical purity of the above obtained product, wide application range, and suitableness for industrial production.
Enantioselective enolate protonation: Matching chiral aniline and substrate acidity
Vedejs,Kruger,Suna
, p. 7863 - 7870 (2007/10/03)
A comparison of chiral anilines 1a-f in the asymmetric protonation of enolate 15 shows that the optimum ΔpK(a) value (chiral acid vs protonated enolate) for the highest enantioselectivity is ca. 3 (Table 2). An extension of this concept to amino acid enolates was possible, and 1e was found to give the best enantioselectivity (85% ee) with the alanine-derived N-lithioenolate 5a (Table 3). Changes in aniline pK(a) due to variation of substituents at the aniline nitrogen were evaluated briefly, but these changes did not show consistent trends in the enantioselectivity vs pK(a).
