Question

Consideration the addition of HBr to 3,3-Dimethyl-1-butene shown below. what is the best mechanism explanation for the formation of the observed product?

• A. Protonation of the alkene followed by a hydride shift and addition of bromide to the carbocaton
• B. Double bond shift in the alkene following by the protonation and addition of bromide to the carbocation
• C. addition to bromide to the alkene followed by a double bond shift and protonation
• D. Protonation of the alkene followed by a methyl shift and addition of bromide to the carbocation

Answer 1

The correct option is D Protonation of the alkene followed by a methyl shift and addition of bromide to the carbocation

This is an addition reaction which involves the formation of carbocation. First protonation of alkene takes place followed by methyl shift to stabilize carbocation. Then addition of bromine takes place.