I think the substituent of option (a) should attack the meta position as the resultant carbanion gets stabilized by an inductive effect, but no such compound is given. So where am I making a mistake?
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asked Jul 7, 2015 at 7:48
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2 Answers
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Your reasoning is quite correct for an uncatalysed reaction. I think you have forgotten about the hydrochloric acid you also add (in catalytic amounts). You will therefore protonate the double bond first, with the carbo cation being more stable in the ortho position. The alcohol can now act as a nucleophile and attack at that carbon. Therefore (c) is the correct answer.
answered Jul 7, 2015 at 8:03
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The reason A is not correct is because this is a different sort of reaction than the one you are referring to. It is an extremely common to mistake cyclohexane or in this case dihydropyran with benzene, an aromatic ring. When the term "meta" is used, it suggests you are applying the rules of electrophilic aromatic substitution to a reaction that involves an aromatic ring. This is not such a case.
This is simply an electrophilic addition with a resonance stabilized carbocation (oxocarbenium) with hydrochloric acid acting as acid catalyst.
What I mean is this following:
