QuestionOrganic / peroxide effect
The major product formed in the reaction of 3-phenylpropene with HBr in the presence of peroxide is:
- (a) 2-Bromo-1-phenylpropane
- (b) 1,2-Dibromo-3-phenylpropane
- (c) 1-Bromo-3-phenylpropane
- (d) 3-(p-Bromophenyl) propene
Answer: (c) 1-Bromo-3-phenylpropane
HBr + peroxide → free-radical, anti-Markovnikov addition. Br• adds to terminal CH₂ to give the more stable 2° radical: PhCH₂CH=CH₂ → PhCH₂CH₂CH₂Br = 1-bromo-3-phenylpropane → (c).