a) Write down the prefered pathways of radical loss for the following molecular ions.
The prefered pathways are determined by benzylic cleavage, alpha-cleavage and allyllic cleavage:
b) The McLafferty rearrangement is one of the important pathways of alkene loss from molecular ions. Write down its mechanism for butanal molecular ion.
The stwo-step mechanism rationalized the reaction better than the originally formulated concerted pathway.
c) Below, four isomeric alkylcyclohexanone molecular ions are shown. Decide which of these can be distiguished from the others by means of their product ions from double-alpha cleavage.
Below, the gamma-positions are highlighted in small red circles.