Determination of the enantiomeric purity of mevalonolactone via NMR using a chiral lanthanide shift reagent.

Simple methods for determining the enantiomeric purity of mevalonolactone and linalool by NMR using the chiral shift reagent Eu(hfc)3 are reported. These methods are more reliable than polarimetry and require only a few milligrams of sample to detect as little as 2% of the minor enantiomer. The accuracy of these methods is limited primarily by spectral resolution for samples of high enantiomeric excess and by errors inherent in measuring peak intensities for samples of low enantiomeric excess. The Cornforth synthesis (Cornforth, R. M., J. W. Cornforth, and G. Popják. 1962. Tetrahedron. 18: 1351-1354) of (S)-mevalonolactone from (R)-linalool has been improved and shown to proceed with negligible racemization.