Direct Assignment of the Threo and Erythro Configurations in Polyacetylene Glycosides by ¹H NMR Spectroscopy

An approach for discriminating the threo and erythro configurations of polyacetylene glycosides by 1H NMR spectroscopy was developed. Using acetic acid-d4/D2O as the solvent, a relatively larger 3JHH value (7.0 Hz) for the acyclic vicinal diol group was unambiguously assigned to the threo configuration, whereas the smaller value (3.5 Hz) was assigned to the erythro configuration. This convenient method requires no hydrolysis or derivatization...