Extensive Substituent Scrambling in Substituted Diphenylacetylenes on Electron Impact

Article abstract of DOI:10.1002/oms.1210241010

Extensive randomization of the substituents is found in mono- and disubstituted diphenylacetylenes under electron impact conditions.The study of diphenylacetylenes with a variety of substituents indicates that the electron-withdrawing groups favour the substituent scrambling.All the substituted diphenylaceetylenes give an ion at m/z 176, having a common ion-structure, arising as a result of the expulsion of a hydrogen radical and the substituent in monosubstituted diphenylacetylenes and the expulsion of both the substituents in disubstituted diphenylacetylenes.A ring-expanded structure is postulated for this common fragment.