1,2-Shift of a Carboxyl Group in a Wagner-Meerwein Rearrangement

Article abstract of DOI:10.1002/hlca.19820650713

On treatment with HSO3F in SO2Cl at 0 deg C, 3-hydroxy-2,2-dimethyl-3-phenylpropionic acid (1a) is trasformed into 2-phenyl-3-methyl-2-butenoic acid (2a) (isolated yield: 40-44percent).Using monolabelled <3-13C>-1a (1a*) and doubly labelled <1,3-13C₂>-1a (1a**), the migration of HOOC (or a mechanistically equivalent group) was proved; a cross experiment established the intramolecular character of the rearrangement.By following the reaction at low temperature in an NMR. spectrometer, the formation of intermediates and side products was demonstrated.