Application of z-COSY experiment and its variant for accurate chiral discrimination by (1)H NMR.

We report the application of z-COSY experiment and a band selected version of it by employing a selective 90 degrees pulse entitled BASE-z-COSY for precise chiral discrimination, quantification of enantiomeric excess and the analyses of the (1)H NMR spectra of chiral molecules aligned in the chiral liquid crystalline solvent poly-gamma-benzyl-l-glutamate (PBLG). We have demonstrated their applicability for obtaining very high resolution in the (1)H NMR spectra of small organic molecules. It is well known that the commonly employed z-COSY experiment disentangles the spectral complexity, provides pure phase spectra with high resolution, aids in the complete spectral analyses, in addition to yielding information on relative signs of the couplings. The BASE-z-COSY experiment possesses all these properties, permits the measure of enantiomeric excess, in addition to large saving of instrument time.