Fundamentals of Organic ChemistryChemistryAlcohols Phenols and Ethers
Consider the following reaction: C ₆ H ₅- O - CH ₂- CH ₃ HI / [ X ] + [ Y ] The products [ X ] and [ Y ] are:
Options
- AC ₆ H ₅ OH and CH ₂= CH ₂
- BC ₆ H ₅ I and CH ₃- CH ₂- I
- CC ₆ H ₅ OH and CH ₃- CH ₂- I
- DC ₆ H ₅ I and CH ₃- CH ₂ OH
Correct answer
C. C ₆ H ₅ OH and CH ₃- CH ₂- I
Step-by-step solution
The given reaction is the cleavage of an alkyl aryl ether by hydroiodic acid ( HI ). First, the ether oxygen is protonated by HI to form an oxonium ion: C ₆ H ₅- O ⁺( H )- CH ₂- CH ₃ . The C ₆ H ₅- O bond has partial double bond character due to the resonance of the lone pair of oxygen with the benzene ring, making it stronger and difficult to break. Therefore, the nucleophile I ⁻ attacks the less sterically hindered CH ₂ carbon of the ethyl group via an S _ N 2 mechanism. This results in the cleavage of the O - CH