Electron impact fragmentation patterns of 3,3-dimethyl-1,2-norbornane derivatives

The electron impact mass spectra of several 3,3-dimethyl-1,2-norbornanediol s, diamines, amino alcohols and related derivatives have been studied and t heir fragmentation pathways discussed. Different fragmentation patterns wer e observed, depending not only on the mature of the substituents, but also on their relative positions on the norbornane framework. In general, the do minant peaks in the spectra of these compounds originate from initial C1-C2 bond cleavage (alpha-cleavage) with charge retention on the heteroatom (ox ygen or nitrogen) attached at the bridgehead position, followed by hydride shift and loss of the C2-C3 fragment by homolytic cleavage of the C3-C4 bon d, This fragmentation pathway leads td a highly stabilized cyclopentenylimm onium or cyclopentenyloxonium ion, which constitutes the base peak in the s pectra in most of the studied compounds, Copyright (C) 1999 John Whey & Son s, Ltd.