2nd LE- alkyl halide

• Alkyl Halides are compounds with a halogen atom bonded to a saturated, sp3 carbon atom
• Organohalides are organic compounds that contain one or more halogen atoms
• Preparing Alkyl Halides

  1. Radical Halogenation of Alkanes
  2. Vinylic and Allylic Bromination of Alkenes
  3. Preparing Alkyl Halides from Alcohols
• Radical Halogenation of Alkanes Undergo 3 steps

  1. Initiation step - with the presence of irradiation of light or hv)
  2. Propagation step (a repeating step)
  3. Termination steps
• Vinylic and Allylic Bromination of Alkenes

  • Vinylic Bromination of Alkenes: Halogenation and Hydrohalogenation of Alkenes. Halogen will bond with vinylic carbon (carbon that participates in the double bond)
  • Allylic Bromination of Alkenes: Halogen will bond with allylic carbon (adjacent carbon to double bond). Will be possible only with N-bromosuccinimide (NBS) in the presence of light.
• Geminal dihalide - both halogens are connected to the same carbon atom.
• Vicinal dihalide - the two halogens are connected to the adjacent carbon atoms.
• Preparing Alkyl Halides from alcohols

  • most generally the useful method for preparing alkyl halide
  • Reactivity: Methyl < Primary < secondary < tertiary
  • Primary and secondary are the best converted as alkyl halides