Stereochemical effects in the mass spectra of 2-hydroxy-, 5-hydroxy- and 2,5-dihydroxyprotoadamantanes

Electron ionization and methane and isobutane chemical ionization mass spectra have been obtained for the four configurationally isomeric 2,5-protoadamantanediols and the corresponding model monoalcohols. Although the electron impact (both 70 and 15 eV) and methane chemical ionization mass spectra of the 2,5-protoadamantanediols are distinct, the variations are not large and in general they are difficult to rationalize in terms of specific structural features. In contrast, the isobutane chemical ionization mass spectra of these diols show significant differences which can easily be correlated with sterochemical orientations of the substituents.