N.m.r. assay of enantiomeric excess

Abstract

The use of (S)-methylmandelate as a Chiral Derivatising Agent for chiral acids is described. The diastereoisomers obtained by esterification are studied by (^1)H.N.M.R. Assignment of absolute configuration in these systems is made using models proposed to explain the origin of diastereotopic methylene proton non-equivalence in camphanamides. The development and application of chiral phosphine platinum (O) and palladium (O) ethene complexes as Chiral Derivatising Agents for chiral alkenes and allenes is reported. The (^31)P N.M.R. spectra recorded for the mixtures of diastereo isomers obtained when the ethene ligand is displaced "in situ" by alkene or allene enantiomers are fully described. Efforts to produce a chiral sulphoxide solvating agent for amines, amides and alcohols proved inconclusive. Enantiomerically enriched 2-Naphthyl- and 9-Anthrylmethyl-sulphoxides were synthesised but neither induced non- equivalence in racemic solvates.0-Acetylmandelic acid has been used as a Chiral Solvating Agent for amines and B-aminoalcohols. Diastereomeric salts formed "in situ" are studied by (^1) H N.M.R The accuracy of the integrated enantiomeric composition measurement is ±2% and the sense of chemical shift non-equivalence is consistent with configuration within related series of compounds.