H-X Addition to Alkenes: Hydrohalogenation

H-X Addition to Alkenes

• Markovnikov addition, no stereochemistry
• Two-step mechanism with carbocation intermediate.
• Regiochemistry is controlled by carbocation stability.
  • 3^o>2^o>1^o>Methyl (Markovnikov's rule)
• Carbocation rearrangements are possible (e.g hydride or alky shifts).
• Evidence for this mechanism is the observed regiochemistry and
  rearrangements.