Which of the following carbocations would not be likely to undergo rearrangement?

a) ch3chchch3 ch3 ch3

b) ch3choch3 ch3 ch

c) ch3cch2 ch3

d) ch3 ch3chch2

e) ch3 ch3cchch2ch3 ch3

C)

Explanation:

The first step is to draw the figures to see where is placed the positive charge. (See figure). Then, we have to remember that a rearrangement only takes place if we go from a primary or secondary carbocation to a tertiary one.

When we check all the structures we can notice that all are secondary carbocation except for C). This structure is already a tertiary carbocation, so in this molecule is not possible a rearrangement because is already a tertiary carbocation.