The behaviour of stereoisomeric ions in the gas phase: 3—The case of homosubstituted bicyclooctenes

In the electron impact mass spectroscopy of four 2,3,5,6-bicyclo(2.2.2)–7-octenetetramethoxycarbonyl stereoisomers differences in relative abaundances of product ions and also different fragmentation pathways are observed. The stereospecificity is retained also under positive ion chemical ionization (CI(methane), CI(isobutane)) and negative ion chemical ionization (NICI) (OH^?) conditions. Interesting correlations between fragmentation and molecular symmetry are suggested.