Ring contraction upon electron‐impact as a function of ring size: The mass spectrometric fragmentation of acylated cyclic amines

This is the authors' abstract. We don't add key points for this paper.

The structural prerequisites of skeletal rearrangement by ring contraction, previously observed in N‐acetylmorpholine, were explored by extending the study to N‐acetylpyrrolidine, ‐piperidine and ‐hexamethyleneimine. Fragmentation via ring contraction was found to be absent in the five‐membered ring, detectable in the six‐membered ring, and significant in the seven‐membered homologue. Ring contraction in these model compounds, i.e. in absence of oxygen as a second heteroatom in the cyclic moiety, is discussed in view of its implications and its support for an initially proposed radical‐induced rearrangement mechanism.