Phenylglycine methyl ester, a useful tool for absolute configuration determination of various chiral carboxylic acids

A new chiral anisotropic reagent, phenylglycine methyl eater (PGME), develo ped for the elucidation of the absolute configuration of chiral alpha,alpha -disubstituted acetic acids, has turned out to be applicable to other subst ituted carboxylic acids, such as chiral alpha-hydroxy-, alpha-alkoxy-, and alpha-acyloxy-alpha,alpha-disubstituted acetic acids, as well as to chiral beta,beta-disubstituted propionic acids. Because a carboxylic moiety is con vertible from other functional groups, e.g., ozonolysis of an olefin and ox idative cleavage of a glycol, the present findings can expand the utility o f the PGME method to the absolute configuration determination of various ty pes of organic compounds, even those which initially lack oxygen functions. Several examples of the combination of chemical reactions and the PGME met hod are described.