An ingenious method for the determination of the relative and absolute configurations of compounds containing aryl-glycerol fragments by 1H NMR spectroscopy

A concise method was established to determine the relative and absolute configurations of aryl-glycerols that depend on the chemical shift differences (Δδ) of the diastereotopic methylene protons (H-3) by 1H NMR spectroscopy. When using DMSO-d6 as the preferred solvent, the threo configuration corresponded to a larger ΔδH3a–H3b value (>0.15 ppm), whereas the erythro configuration ( 0.20 ppm. In the erythro enantiomers, the Δδ value of 1R,2S was >0.09 ppm, and that of 1S,2R was <0.05 ppm. Remarkably, this empirical rule is invalid in CDCl3. In addition, this method was also verified by a quantum 1H NMR calculation.