Question

The major products M and N formed in the following reaction sequence are

• A. A
• B. B
• C. C
• D. D

Hint:

McMurry coupling converts carbonyl compounds into alkenesAnti addition of Br$_2$ to a trans alkene generally gives a meso product

Answer 1

The Correct Option is D

Step 1: First reagent.
TiCl$_3$ with Zn-Cu is a McMurry coupling, which joins two carbonyl groups into an alkene.

Step 2: Product M.
Two molecules of acetophenone couple to give the more stable trans alkene, trans-2,3-diphenyl-2-butene.

Step 3: Reaction with bromine.
Bromine adds across the double bond in an anti fashion.

Step 4: Product N.
Anti addition to the trans alkene gives the meso dibromide.

Step 5: Answer.
\[ \boxed{\text{D}} \]