Abstract:

McLafferty rearrangement is an empirical rule proposed for the rearrangement of molecular ions in mass spectrometry. Further expanding the concept, cleaving process and application of classic McLafferty rearrangement, the general McLafferty rearrangement is formed. In the general McLafferty rearrangement, the γ-H transference of six-membered ring cooperatively completes in one step. The cooperative rearrangement of molecular ions can also occur through a six-membered or five-membered ring transition state and the γ-R or β-H (R) of molecular ions accomplishes the transference, which results in different fragment ions. This general McLafferty rearrangement can occur in various compounds with most functional group, which is helpful in mass spectrometry analysis and compound structure research and extend the breadth of the applications.

Key words: General McLafferty rearrangement, Cooperative cleavage, Six-membered ring, Five-membered ring