Q20E - Organic Chemistry (Mcmurry)

Question

In light of the fact that tertiary alkyl halides undergo spontaneous dissociation to yield a carbocation plus halide ion (see Problem 10-45), propose a mechanism for the following reaction.

Step-by-Step Solution

Answer

The mechanism is as follows:

Step 1: Formation of tert-butyl carbocation

This step is slow and rate determining step. A more stable tert-butyl carbocation is formed in this step. The carbocation is more stable due to hyperconjugation and it leaves behind bromide anion.

Step 2: SN 1 pathway

During this step, HOH attacks on the carbocation, due to which loss of proton takes place. This results in the removal of the hydrogen from the carbon adjacent to the carbocation. As a result, we get the desired product.

The reaction is as follows: