Question

Which of the following cannot be made by using Williamson's synthesis?

• A. Methoxybenzene
• B. Benzyl p-nitrophenyl ether
• C. Methyl tertiary butyl ether
• D. Di-tert-butyl ether

Hint:

Williamson’s synthesis works best with primary alkyl halides and fails with tertiary alkyl halides due to steric hindrance.

Answer 1

The Correct Option is D

Step 1: Understanding Williamson's synthesis.
- Williamson’s synthesis involves the reaction of an alkoxide ion (\( R-O^- \)) with a primary alkyl halide (\( R'-X \)) via the SN2 mechanism.
- The reaction does not work well with tertiary alkyl halides due to steric hindrance, which favors elimination over substitution.
Step 2: Identifying the correct option.
- In di-tert-butyl ether (\( (CH_3)_3C-O-(CH_3)_3C \)), both alkyl groups are tertiary.
- The SN2 reaction fails for tertiary alkyl halides because they form carbocations, leading to elimination instead of substitution.
- Therefore, di-tert-butyl ether cannot be synthesized using Williamson’s synthesis.