Question

Provide the structures of the fragments that result when the molecular ion of 2-heptanone undergoes fragmentation via McLafferty rearrangement. Include charges and single electrons.

Answer 1

See explanation

Step-by-step explanation:

We have to start, remembering the mechanism behind the McLafferty rearrangement. The hydrogen in the gamma carbon (in this case, carbon 5) would be removed by a heterolytic rupture due to the cation-radical placed in the oxygen of the carbonyl group. Then we will have several heterolytic ruptures. Between carbons alpha and beta (in this case, 4 and 3) and a rupture in the carbonyl group. Due to these ruptures, two double bonds would be formed. One double bond in the alcohol cation-radical and the other one in the alkene.

See figure 1

I hope it helps!