A general method is described for determining enantiomeric purities of chiral lactones, regardless of their ring size. The approach involves treatment of a lactone with methyllithium, followed by NMR examination of the diol produced in the presence of a chiral shift reagent such as Eu (tfc) 3. The method is broadly applicable to a wide range of variously substituted 7-, 6-, and elactones. Its accuracy for enantiomeric excess determinations is f3, 6. This has ...
