Question

The number of optically active products obtained from the complete ozonolysis of the given compound is :

• A. 0
• B. 2
• C. 4
• D. 4

Hint:

When analyzing ozonolysis of chiral compounds, carefully consider the stereochemistry at the chiral centers and how they are retained (or lost) in the products. If the ozonolysis generates chiral products, remember that each chiral compound contributes one optically active product (and its enantiomer is another optically active product).

Answer 1

The Correct Option is B

Step 1: Understand ozonolysis of alkenes.
Ozonolysis of alkenes followed by reductive workup yields carbonyl compounds. The carbon-carbon double bonds are cleaved, and oxygen atoms are attached to the carbon atoms of the double bond, forming aldehydes or ketones.
Step 2: Identify the chiral centers and the products of ozonolysis.
The given compound has two chiral centers with opposite configurations. Ozonolysis will cleave the three double bonds, resulting in the following organic products:
1. \( CH_3CHO \) (ethanal - achiral) 2. \( H-\overset{CH_3}{\underset{H}{\mathrm{C}^}}-CHO \) (2-methylpropanal - chiral) 3. \( OHC-CHO \) (glyoxal - achiral) 4. \( OHC-\overset{H}{\underset{CH_3}{\mathrm{C}^}}-CHO \) (2-methylmalondialdehyde - chiral) 5. \( OHC-CHO \) (glyoxal - achiral)
Step 3: Determine the number of optically active products.
The chiral products formed are 2-methylpropanal and 2-methylmalondialdehyde. Due to the opposite configurations at the chiral centers in the starting material, the resulting chiral aldehydes will be enantiomers of each other. The first chiral center yields one enantiomer of 2-methylpropanal.
The second chiral center yields the other enantiomer of 2-methylpropanal.
These two enantiomers are the optically active products. Glyoxal and ethanal are achiral. Therefore, the number of optically active products is 2.