Preparing Alkyl Halides from Alkenes: Allylic Bromination Alkyl halides can also be prepared from alkenes by reaction with N- bromosuccinimide(NBS)in the presence of light Bromine is substituted for hydrogen at the position next to the double bond-the allylic position HH N-Br (NBS) Br Allylic positions hy,CCla H H Cyclohexene 3-Bromocyclohexene (85%)Alkyl halides can also be prepared from alkenes by reaction with N￾bromosuccinimide (NBS) in the presence of light ▪ Bromine is substituted for hydrogen at the position next to the double bond – the allylic position Preparing Alkyl Halides from Alkenes: Allylic Bromination