Fundamentals of Organic ChemistryChemistryAlcohols Phenols and Ethers
Identify the products A and B in the following reaction sequence: B H ⁺ KMnO ₄ ( CH ₃ )₃ COH KMnO ₄ / OH ⁻ A
Options
- AA and B both are ( CH ₃ )₂ CO + CH ₂ O
- BA and B both are ( CH ₃ )₂ C = CH ₂
- CA is ( CH ₃ )₃ COH , while B is ( CH ₃ )₂ C = CH ₂ or ( CH ₃ )₂ CO
- DA and B both are ( CH ₃ )₃ COH (i.e., there is no reaction)
Correct answer
C. A is ( CH ₃ )₃ COH , while B is ( CH ₃ )₂ C = CH ₂ or ( CH ₃ )₂ CO
Step-by-step solution
Tertiary alcohols are resistant to oxidation under neutral or alkaline conditions. Therefore, when treated with alkaline KMnO ₄ ( KMnO ₄ / OH ⁻ ), no reaction occurs and product A is the unreacted starting material, ( CH ₃ )₃ COH . Under acidic conditions ( KMnO ₄ / H ⁺ ), tertiary alcohols undergo dehydration to form alkenes. Thus, ( CH ₃ )₃ COH dehydrates to give isobutylene, ( CH ₃ )₂ C = CH ₂ . The resulting alkene can further undergo oxidative cleavage by the strong oxidizing agent (acidic KMnO ₄ ) to yield a