Determination of the Enantiomeric and Optical Purity of a-Phosphoryl Sulfoxide 1 by NMR. Resolution is often deemed complete once the enantiomers are obtained with equal and opposite specific rotations. This criterion, however, has limited precision and since in our case it was not fulfilled, an independent establishment of the optical purity of enantiomeric sulfoxides 1 was desirable. We employed, therefore, a chiral lanthanide shift reagent, tris-[ ...
