Question

Consider the following sequence of reactions:



The major product $P$ is:

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

First, dehydrate the tertiary alcohol using hot copper to get an alkene. Then, perform an acid-catalyzed addition of benzoic acid to that alkene to form an ester following Markovnikov's logic.

Answer 1

The Correct Option is C

Let's analyze the reaction sequence pathway:

Step 1: Dehydration of the Alcohol
The starting material is tert-butyl alcohol. Treating a tertiary alcohol with heated copper ($Cu$) at $300^\circ C$ (573 K) causes dehydration because the alcohol lacks an alpha-hydrogen for oxidation to a carbonyl group. The product is the alkene 2-methylpropene ($CH_2=C(CH_3)_2$).

Step 2: Electrophilic Addition (Esterification)
The alkene reacts with benzoic acid ($PhCOOH$) in the presence of an acid catalyst ($H^+$). The mechanism involves:
1. Protonation of the alkene to form the most stable carbocation intermediate (the tert-butyl carbocation, $(CH_3)_3C^+$).
2. Nucleophilic attack by the benzoic acid carboxylate oxygen on the carbocation.
3. Deprotonation to yield the ester $Ph-C(=O)-O-C(CH_3)_3$.

This ester is tert-butyl benzoate. Among the choices provided, option 3 represents this product correctly.