Alkanes

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Alkanes

  1. 1. Preparation Reactions of Alkanes Reduction reactions Alkene hydrogenation Alkyne hydrogenation Alkyl halide hydride reduction Alkyl halide zinc/acid reduction Grignard formation/destruction Coupling reactions Wurtz reaction Corey-House coupling
  2. 2. Preparation of Alkanes via Reduction Hydrogenation of Alkenes Hydrogenation of Alkynes R R R R H2 /Pt C C CH CH R R R R H H H2 /Pt R C C R R C C R H H
  3. 3. Preparation of Alkanes via Reduction Alkyl halide reduction via lithium aluminum hydrideAlkyl halide reduction via zinc / acid H H H + LiAlH 4 Zn/H R C R R C R R C R ether X H X
  4. 4. Formation / Destruction of Grignard reagents Mg R C X R C Mg X ether an alkyl halide a Grignard reagent R C Mg X R C H + Mg(OH)X H2 O alkane
  5. 5. Coupling Reactions Wurtz reaction2R C X Na R C C R + 2NaX a symmetrical alkane
  6. 6. Coupling ReactionsCorey-House coupling (Gilman Li reagent) R X R Li + LiX CuX R 2R Li Cu Li + LiX R an organocuprate (Gilman reagent)R Cu Li + R X R R + R Cu + LiXR
  7. 7. Halogenation of Alkanes Selectivity / Reactivity F2 Case I: CH3 CH2 CH3 FCH2 CH2 CH3 + CH3 CH(F)CH3 u.v. o 75% 25% 25 C Cl2 Case II: CH3 CH2 CH3 ClCH2 CH2 CH3 + CH3 CH(Cl)CH3 u.v. o 45% 55% 25 C Br 2 Case III: CH3 CH2 CH3 BrCH2 CH2 CH3 + CH3 CH(Br)CH3 u.v. o 3% 97% 125 C

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