TY - JOUR
T1 - The self-disproportionation of enantiomers (SDE) of α-amino acid derivatives
T2 - facets of steric and electronic properties
AU - Hosaka, Takuma
AU - Imai, Tomomi
AU - Wzorek, Alicja
AU - Marcinkowska, Magdalena
AU - Kolbus, Anna
AU - Kitagawa, Osamu
AU - Soloshonok, Vadim A.
AU - Klika, Karel D.
PY - 2019/2/7
Y1 - 2019/2/7
N2 - α-Amino acids (α-AAs) are in extremely high demand in nearly every sector of the food and health-related chemical industries and continue to be the subject of intense multidisciplinary research. The self-disproportionation of enantiomers (SDE) is an emerging and one of the least studied areas of α-AA or enantiomeric properties, critically important for their production and application. In the present work, we report a detailed study of the SDE via achiral, gravity-driven column chromatography for a set of N-acylated, N-carbonylated, N-fluoroacylated, and N-thioacylated α-amino acid esters. As well as thioacylation, attention was paid to the effect of altering the R group of the ester functionality, the side chain, or that of the acyl group attached to the amide nitrogen, whereby it was found that electron-withdrawing groups in the latter moiety had a pronounced effect on the magnitude and behavior of the resulting SDE phenomenon. Intriguingly, in the case of N-fluoroacylated derivatives, by favoring the formation of dimeric associates and effecting a strong bias toward homochiral associates over heterochiral associates, the SDE magnitude was greatly reduced contrary to intuitive expectations. Energy estimates resulted from DFT calculations.
AB - α-Amino acids (α-AAs) are in extremely high demand in nearly every sector of the food and health-related chemical industries and continue to be the subject of intense multidisciplinary research. The self-disproportionation of enantiomers (SDE) is an emerging and one of the least studied areas of α-AA or enantiomeric properties, critically important for their production and application. In the present work, we report a detailed study of the SDE via achiral, gravity-driven column chromatography for a set of N-acylated, N-carbonylated, N-fluoroacylated, and N-thioacylated α-amino acid esters. As well as thioacylation, attention was paid to the effect of altering the R group of the ester functionality, the side chain, or that of the acyl group attached to the amide nitrogen, whereby it was found that electron-withdrawing groups in the latter moiety had a pronounced effect on the magnitude and behavior of the resulting SDE phenomenon. Intriguingly, in the case of N-fluoroacylated derivatives, by favoring the formation of dimeric associates and effecting a strong bias toward homochiral associates over heterochiral associates, the SDE magnitude was greatly reduced contrary to intuitive expectations. Energy estimates resulted from DFT calculations.
KW - Achiral column chromatography
KW - DFT calculations
KW - Enantioenrichment/-depletion
KW - Molecular chirality
KW - N-(Thio)acylated α-amino acid esters
KW - Self-disproportionation of enantiomers (SDE)
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U2 - 10.1007/s00726-018-2664-x
DO - 10.1007/s00726-018-2664-x
M3 - Article
C2 - 30311082
AN - SCOPUS:85055088801
VL - 51
SP - 283
EP - 294
JO - Amino Acids
JF - Amino Acids
SN - 0939-4451
IS - 2
ER -