Chiral differentiation of some cyclic beta-amino acids by kinetic and fixed ligand methods.
Differentiation of beta-amino acid enantiomers with two chiral centres was investigated by kinetic method with trimeric metal-bound complexes. Four enantiomeric pairs of beta-amino acids were studied: cis-(1R,2S)-, cis-(1S,2R)-, trans-(1R,2R)- and trans-(1S,2S)-2-aminocyclopentanecarboxylic acids (cyclopentane beta-amino acids), and cis-(1R,2S)-, cis-(1S,2R)-, trans-(1R,2R)-, and trans-(1S,2S)-2-aminocyclohexanecarboxylic acids (cyclohexane beta-amino acids). The results showed that the choice of metal ion (Cu(2+), Ni(2+)) and chiral reference compound (alpha- and beta-amino acids) had an effect on the enantioselectivity. Especially, aromaticity of the reference compound was noted to enhance the enantioselectivity. The fixed-ligand kinetic method, a modification of the kinetic method, was then applied to the same beta-amino acids, with dipeptides used as fixed ligands. With this method, dipeptide containing an aromatic side chain enhanced the enantioselectivity.
Hyyryläinen
Anna R M
AR
Department of Chemistry, University of Joensuu, P.O. Box 111, FI-80101 Joensuu, Finland.
Pakarinen
Jaana M H
JM
Forró
Enik
E
Fülöp
Ferenc
F
Vainiotalo
Pirjo
P
D000598:Amino Acids, Cyclic / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D003509:Cyclohexanecarboxylic Acids / Q000737:chemistry; D003514:Cyclohexylamines / Q000737:chemistry; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000737:chemistry; D007700:Kinetics; D008024:Ligands; D009532:Nickel / Q000737:chemistry; D013237:Stereoisomerism
D000598:Amino Acids, Cyclic; D003509:Cyclohexanecarboxylic Acids; D003514:Cyclohexylamines; D008024:Ligands; D003515:Cycloleucine; C065594:cispentacin; C103271:2-aminocyclohexanecarboxylic acid; D003300:Copper; D009532:Nickel