Electrophilic addition reactions to nonconjugated alkadienes can occur at one or both double bonds. These reactions occur by 1,2-addition, and we can use Markovnikov’s rule to predict the major products. Sign in to download full-size image The addition of HBr to a conjugated diene is striki...
of two pi electrons from the double bond, as shown by the curved arrow. A C-H sigma bond is formed between HBr and a carbon in the double bond formed by the two pi electrons. In a matter of seconds, the electrons from the hydrogen-x bond are transferred to the halogen to form a ...