Determination of relative configuration of symmetrical bis-Tröger’s base derivatives

Determination of the molecular covalent structure based on spectral analyses is almost routine; however, estimation of stereostructure is still challenging, particularly in case of symmetrical molecules. In this study, various spectral (NMR, IR and Raman) markers revealing relative configuration (syn and anti) of bis-Tröger’s base diastereoisomers are identified. Differences in diastereoisomers 1H chemical shifts seem to be most useful, as they can be interpreted by computations. Vibrational spectra of syn and anti diastereoisomers exhibited systematic differences, too. The relative configuration can be also predicted based on retention on silica, and unambiguously confirmed via chromatographic analysis on a chiral stationary phase.

► Determination of relative configurations of bis-Tröger’s bases.
► Comparison of experimental and calculated 1H chemical shifts.
► Detailed analysis of infrared and Raman spectra to distinguish diastereoisomers.
► Chromatographic methods for determination of relative configurations.