Limitations in determining enantiomeric excess of alcohols by P-31-NMR of the phosphonate derivatives

The use of diastereomeric alcohol dialkylphosphonate derivatives to determi ne the enantiomeric excesses via P-31-NMR signal ratios of anisochronous me so and three isomers was successfully applied to secondary alcohols (Fering a's method). Expansion of the methodology to primary alcohols possessing th e hydroxyl groups thethered to the stereogenic centers by two or more methy lene groups proved the method to be inefficent. The comparison between the coupled and decoupled spectra is important in order to identify the signals corresponding to the dialkylphosphonates. Nevertheless the methodology sho uld be applied whenever the amount of the alcohol and its structure are not the limiting factors.