Chapter G, Problem G.8YT

Interpretation Introduction

Interpretation:

The McLafferty rearrangement for the molecular ion of pentanoic acid is to be drawn.

Concept introduction:

These two fragmentation pathways – heterolysis and α-cleavage – are also common to other compound classes that have functional groups with heteroatoms, such as amines, ethers, and alcohols. Depending on the identity of the functional group as well as the specific structure of the compound, one of these fragmentation pathways can be highly favored over the other.

In addition to α-cleavage, there is another fragmentation pathway characteristic of carbonyl-containing compounds. A carbonyl-containing compound can undergo a McLafferty rearrangement if an alkyl group attached to the carbonyl carbon possesses a $\text{γ}$-carbon with at least one hydrogen atom.