Why would the following mechanism be valid for the conversion of t-butylbenzene to benzene in highly acidic medium followed by an aqueous workup?
The main problem I have with this mechanism is the formation of the secondary doubly allylic carbocation. Why not go for the tertiary, inductively and doubly allylic stabilized carbocation?
But I guess the problem with going down this path it becomes hard to see how the t-butyl group might leave.
As you can see, the book's mechanism is entirely dependent on having the secondary allylic carbocation.