Szcmmary threo-3-Hydroxycarboxylic acids, which are enol ethers with the triphenylphosphinediethyl azostereoselectively obtained from metallated carboxylic dicarboxylate-adduct, whereas the corresponding (E)acids and aldehydes, are converted into (, %' )-ol efi ns and isomers are prepared via the p-lactones.

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For the enantioselective oxidation of methyl phenyl sulfide and tert-butyl methyl sulfide to the corresponding chiral sulfoxides by 3,3-dibromo-(camphorsulfonyl)oxaziridine, semiempirical calculations (MNDO, AMI, PM3) concerning transition state geometries were performed. The results show that only PM3 is able to localize a transition state. For methyl phenyl sulfide, a spiro arrangement of the oxaziridine ring and the sulfur atom explains the observed direction of the selectivity better than a planar transition state. The solvent dependence of the observed enantioselectivity is related to the calculated dipole moment of the transition state by the Kirkwood-Onsager model. In THF as solvent, its direct participation in the transition state has to be considered