A simple 13C NMR method for determination of the relative stereochemistry of 2,3-dialkylpentenoic acids and related compounds

The relative stereochemistry of 2,3-dialkylpentenoic acids and derivatives thereof can be easily determined by comparison of 13C NMR spectra of the syn and anti isomers. The chemical shifts of several of the resonances of the anti isomer lie downfield relative to the syn isomer.