Question

The major product P formed in the following transformation is

• A. A
• B. B
• C. C
• D. D

Hint:

MnO$_2$ selectively oxidizes benzylic alcohols, PBr$_3$ converts alcohols into bromides, and base then gives elimination to form the conjugated enone

Answer 1

The Correct Option is A

Step 1: Selective oxidation.
Manganese dioxide oxidises only the benzylic alcohol to a ketone and leaves the primary alcohol untouched.

Step 2: Make the bromide.
Phosphorus tribromide turns the remaining primary alcohol into a primary bromide.

Step 3: Base induced elimination.
Sodium ethoxide removes an alpha hydrogen and eliminates bromide to give a conjugated enone.

Step 4: Answer.
\[ \boxed{\text{A}} \]