[1H, 13C NMR and stereochemistry studies of 3S-substituted alkoxylquinuclidine by two-dimensional and NOE difference NMR techniques].

By using optically pure 3S-quinuclidinol, two diastereoisomers (3S-1) and (3S-2) of 3-(substituted) alkoxy-quinuclidine were synthesized. 1H and 13C NMR spectra of (3S-1) and (3S-2) have been completely analyzed utilizing double-quantum filtered COSY, 13C-1H COSY and NOE difference experiment. The NOE difference experiment was used to determine the absolute configuration at C-11 of the diastereomers. According to the results of NOE difference and variable concentration NMR experiments, the configuration about C-11 of (3S-1) is designated as R (1A), whereas the configuration about C-11 of (3S-2) is designated as S (1B). The result was confirmed by X-ray diffraction analysis.