Question

Identify the major product of the following reaction

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

Clemmensen reduction \((Zn-Hg/HCl)\) converts aldehydes and ketones into hydrocarbons under strongly acidic conditions. Alcohol groups may undergo substitution reactions in concentrated \(HCl\).

Answer 1

The Correct Option is C

Step 1: Identify the reagent used.
The reagents used are:
\[ Zn-Hg \quad \text{and} \quad HCl \] This combination represents

Clemmensen reduction.
Clemmensen reduction converts carbonyl groups \((C=O)\) of aldehydes and ketones into methylene groups \((CH_2)\) under strongly acidic conditions.
General reaction:
\[ R-CO-R' \xrightarrow[HCl]{Zn-Hg} R-CH_2-R' \]

Step 2: Identify the functional groups present in the substrate.
The given compound contains:
(i) A ketone group and \[ \text{(ii) An alcohol group } (-OH) \] The ketone side chain attached to the cyclohexane ring undergoes Clemmensen reduction.

Step 3: Reduction of the ketone group.
The ketone group:
\[ -COCH_3 \] is reduced into:
\[ -CH_2CH_3 \] Thus, the acyl side chain becomes an ethyl group after reduction.

Step 4: Effect of acidic medium on alcohol group.
The reaction occurs in concentrated hydrochloric acid.
Under strongly acidic conditions, the alcohol group on the cyclohexane ring undergoes substitution with chlorine.
Therefore:
\[ -OH \longrightarrow -Cl \] Hence, the final product contains:
Ethyl group and chlorine substituent

Step 5: Identify the final product.
The product obtained is the chlorinated cyclohexane derivative shown in option (3).

Step 6: Final conclusion.
Hence, the correct answer is:
\[ \boxed{\text{Option (3)}} \]