| Abstract: | In contradiction of long-accepted mass spectrometric dogma, the site-specific γ-hydrogen rearrangement is observed in alkylbenzenes in which both ortho positions are blocked with methyl substituents. Mass spectrometric studies of a series of five trimethyl- and three tetramethylisopentylbenzenes have shown that this rearrangement is only suppressed to a significant degree in those compounds in which all three positions ortho and para to the isopentyl group are blocked. Deuterium labelling has confirmed the γ-site-specific origin of the migrating H atom while metastable studies have been used to investigate the mechanism of the rearrangement process. |
