CD exciton chirality method for determination of the absolute configuration of β-hydroxy-α-amino acid derivatives

Abstract

The absolute configuration of β-hydroxyα-amino acids was studied by CD exciton chirality method using 7-diethylaminocoumarin-3-carboxylate as a redshifted chromophore. The CD spectra of bischromophoric derivatives of (S)-serine and (2S,3R)-threonine methyl esters (2 and 7) were compared with those of acyclic vic-aminoalcohols and diols (3-6 and 8-9). This study indicates that the polar carboxylate group of β-hydroxyα-amino acids makes them a unique subclass of vic-aminoalcohols. By combining the data of CD and NMR coupling constants, we are able to correlate their preferred conformer B and positive CD to the corresponding absolute configuration. © 2001 Wiley-Liss, Inc.