How many products (including stereoisomers) are expected from monochlorination of the following compound? (2-methylbutane, i.e. (…

Question

How many products (including stereoisomers) are expected from monochlorination of the following compound? (2-methylbutane, i.e. (CH3)2CH-CH2-CH3)

1. A. 2
2. B. 3
3. C. 5
4. D. 6 (Correct answer)

Correct Answer

Option D — 6

Detailed Solution & Explanation

The correct answer is 6.

Key Points

• 2-Methylbutane has four types of hydrogens, giving four constitutional monochloro products.
• Chlorination at the C-2 (giving 2-chloro-3-methylbutane... i.e. (CH$_3$)$_2$CH-CHCl-CH$_3$) and at the terminal CH$_3$ of the ethyl side (ClCH$_2$-CH(CH$_3$)-CH$_2$CH$_3$) each create a chiral carbon, so each of those gives 2 stereoisomers.
• The other two products (1-chloro at an isopropyl methyl, and 2-chloro-2-methylbutane) have no chiral centre: 1 isomer each.
• Total $=1+2+1+2=6$ products.