McLafferty rearrangement


The McLafferty rearrangement is a reaction observed in mass spectrometry during the fragmentation or dissociation of organic molecules. It is sometimes found that a molecule containing a keto-group undergoes β-cleavage, with the gain of the γ-hydrogen atom, as first reported by Nicholson working in the Division of Chemical Physics at the CSIRO in Australia. This rearrangement may take place by a radical or ionic mechanism.

The reaction

A description of the reaction was later published by the American chemist Fred McLafferty in 1959 leading to his name being associated with the process.