Monosaccharides as internal probes for the determination of the absolute configuration of 2-butanol.

D-Glucose, D-mannose and L-rhamnose were reacted with a racemic mixture of 2-butanol, and the resulting alpha-glycosides were analyzed by 1H NMR with COSY and NOESY experiments. Conformational analysis of alpha-glycosidic bonds performed with molecular modeling and appropriate heteronuclear long-range coupling measurements and combined with analysis of dipolar couplings observed in NOESY spectra allowed the assignment of absolute configuration in the aglycones of elucidated alpha-glycosides.