SEARCH FOR CHARGE-REMOTE REACTIONS OF EVEN-ELECTRON ORGANIC NEGATIVE-IONS IN THE GAS-PHASE - ANIONS DERIVED FROM DISUBSTITUTED ADAMANTANES

The collision induced decompositions of 3-substituted adamantanecarbox ylate anions have been studied with a view to uncover charge-remote fr agmentations of the 3-substituent, The 3-substituent is chosen so that it cannot approach the anion site and therefore any fragmentations of that substituent should proceed independently of the charged centre. (i) Charge-remote radical losses are observed from a 3-CH(Et), substit uent [e.g. Et-. and (CH)-C-.(Et), losses], but the classical Adams-Gro ss charge remote loss of an ethene plus dihydrogen is not observed. (i i) Charge-remote loss of MeOD is observed from a 3-C(CD3)(2)(OMe) subs tituent together with a number of charge-remote radical losses [e.g. M e-., MeO. and C-.(CD3)(2)(OMe)], (iii) The 3-substituent C(CD3)(2) (OC H=O) undergoes charge-remote loss of HCO2D for both the carboxylate an ion and its corresponding cation, a neutral reaction analogous to both the McLafferty rearrangement of radical cations and the Norrish II di radical rearrangement of aliphatic ketones, (iv) The charge-remote rad ical losses of MeO. and (CO2Me)-C-. occur from a 3-CO2Me substituent.