McLafferty rearrangement
The McLafferty rearrangement is a fragmentation reaction observed in mass spectrometry of organic molecules in which the parent radical cation splits into daughter radical cation and neutral spin-paired molecule. 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 Anthony Nicholson working in the Division of Chemical Physics at the CSIRO in Australia. This rearrangement is a retro-ene reaction, and a member of the sigmatropic family of reactions.