2-Methoxy-2- propionic acid determination

It may be mentioned that the diastereomers of the analogous compound bearing a hydrogen atom instead of the methoxy group, the (—-)-methyl esters of 3-(methyl-l-naphthylphenylstannyl)propionic acid, could not be separated analogously. Moreover, NMR spectroscopy could not be used as in the former case to determine the diastereomeric ratio. 

Importantly we could prepare enantiopure 2-methoxy-2-(l-naphthyl)propionic acid (MaNP acid) (X)-(- -)-3 via several reactions from diol (5)-(—)-42 (Figure 55.12)." As will be discussed, the AC of MaNP acid 3 was independently determined by X-ray crystallographic studies of a 1 1 complex of 9-D-(fcrf-butylcarbamoyl)quinine, an ester prepared with ( )-menthol, and an amide formed with (S)-... 

Harada N, Watanabe M, Kuwahara S, Sugio A, Kasai Y, Ichikawa A. 2-Methoxy-2-(l-naphthyl)propionic acid, a powerful chiral auxiliary for enantioresolution of alcohols and determination of their absolute configurations by the H NMR anisotropy method. Tetrahedron Asymm. 2000 1 1249-1253. 

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