Question on the addition of HBr?

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1 Answer
Apr 19, 2018

This is a weird question.

Consider #("a")#

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On the premise that hydrohalogenation has Markovnikov regioselectivity, compound one would have higher preference for this product,

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because a carbocation intermediate on the primary carbon would be extremely unstable and would have a low yield for the other possible product.

Alternatively a secondary or tertiary carbocation don't have as large a stability difference relative to the preceding discussion.

Hence, the first has higher regioselectivity.

In #("b")#, you're right.