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Hydrogen Bond Assisted l to d Conversion of α‐Amino Acids
Author(s) -
Fu Rui,
So Soon Mog,
Lough Alan J.,
Chin Jik
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201914797
Subject(s) - enantiopure drug , chemistry , hydrogen bond , diastereomer , amino acid , epimer , hydrolysis , guanidine , yield (engineering) , stereochemistry , organic chemistry , catalysis , molecule , enantioselective synthesis , materials science , biochemistry , metallurgy
Abstract l to d conversion of unactivated α‐amino acids was achieved by solubility‐induced diastereomer transformation (SIDT). Ternary complexes of an α‐amino acid with 3,5‐dichlorosalicylaldehyde and a chiral guanidine (derived from corresponding chiral vicinal diamine) were obtained in good yield as diastereomerically pure imino acid salt complexes and were hydrolysed to obtain enantiopure α‐amino acids. A combination of DFT computation, NMR spectroscopy, and crystal structure provide detailed insight into how two types of strong hydrogen bonds assist in rapid epimerization of the complexes that is essential for SIDT.