TY - JOUR
T1 - Non-Enzymatic Hybrid Catalysis for Stereoconversion of l-Amino Acid Derivatives to d-Isomers
AU - Nagato, Yuya
AU - Kiyokawa, Mari
AU - Ueki, Yusuke
AU - Kikuchi, Jun
AU - Ohmatsu, Kohsuke
AU - Terada, Masahiro
AU - Ooi, Takashi
PY - 2020/4/1
Y1 - 2020/4/1
N2 - A catalytic transformation of N-unprotected l-amino esters to N-protected d-amino esters was developed. The combined use of a heteroaromatic aldehyde, Lewis acid, palladium complex, and chiral Brønsted acid was a key factor for the successful operation of this catalytic system. The synergistic cooperation of an appropriate aldehyde and Lewis acid was crucial for promoting an efficient racemization of l-amino esters, while the combination of a palladium complex and chiral phosphoric acid enabled dynamic kinetic resolution through asymmetric N-allylation, providing N-protected d-amino esters in good yields with up to 97 : 3 er. Following appropriate deprotection processes, d-amino acids were obtained without loss of enantiomeric purity.
AB - A catalytic transformation of N-unprotected l-amino esters to N-protected d-amino esters was developed. The combined use of a heteroaromatic aldehyde, Lewis acid, palladium complex, and chiral Brønsted acid was a key factor for the successful operation of this catalytic system. The synergistic cooperation of an appropriate aldehyde and Lewis acid was crucial for promoting an efficient racemization of l-amino esters, while the combination of a palladium complex and chiral phosphoric acid enabled dynamic kinetic resolution through asymmetric N-allylation, providing N-protected d-amino esters in good yields with up to 97 : 3 er. Following appropriate deprotection processes, d-amino acids were obtained without loss of enantiomeric purity.
KW - allylic alkylation
KW - d-amino acid
KW - dynamic kinetic resolution
KW - hybrid catalysis
KW - palladium
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U2 - 10.1002/ajoc.202000067
DO - 10.1002/ajoc.202000067
M3 - Article
AN - SCOPUS:85079766036
VL - 9
SP - 561
EP - 565
JO - Asian Journal of Organic Chemistry
JF - Asian Journal of Organic Chemistry
SN - 2193-5807
IS - 4
ER -