The substitution reaction of an alkyl halide mainly occurs by the SN1 or SN2 mechanism. Whatever mechanism alkyl halides follow for the substitution reaction to occur, the polarity of the carbon-halogen bond is responsible for these substitution reactions. The rate of SN1 reactions is governed by the stability of the carbocation, whereas for SN2 reactions the steric factor is the deciding factor. If the starting material is a chiral compound, we may end up with an inverted product or a racemic mixture depending upon the type of mechanism followed by the alkyl halide. Cleavage of ethers with HI is also governed by the steric factor and the stability of the carbocation, which indicates that in organic chemistry these two major factors help us in deciding the kind of product formed.
Write the structures of the products formed when anisole is treated with HI.
Write the structures of the products formed when anisole is treated with HI.
Answer: C₆H₅OH (phenol) + CH₃I — cleavage occurs at the O–CH₃ bond.
Solution
HI cleaves the ether at the weaker O–alkyl bond; the O–aryl bond (partial double-bond character) stays intact:
Products: \textbf{phenol and methyl iodide}.
Products: \textbf{phenol and methyl iodide}.
CBSE Class 12 Board · 2020 · Subjective