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Friedel–Crafts Acylation Reactions

Friedel–Crafts Acylation Reactions. The electrophile is an acylium ion. Mechanism for Friedel-Crafts acylation. Must be carried out with more than one equivalent of AlCl 3. Friedel-Crafts Alkylation of Benzene. Mechanism for Friedel-Crafts alkylation.

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Friedel–Crafts Acylation Reactions

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  1. Friedel–Crafts Acylation Reactions The electrophile is an acylium ion

  2. Mechanism for Friedel-Crafts acylation Must be carried out with more than one equivalent of AlCl3

  3. Friedel-Crafts Alkylation of Benzene

  4. Mechanism for Friedel-Crafts alkylation

  5. The carbocation will rearrange to a more stable species

  6. However, a 100% of the 2-methyl-2-phenylbutane product can be obtained if a bulky alkyl halide is used

  7. It is not possible to obtain a good yield of an alkylbenzene containing a straight-chain group via Friedel–Crafts alkylation due to carbocation rearrangement Acylium ions, however, do not rearrange

  8. Methodologies Used for the Reduction Step

  9. Using Coupling Reactions to Alkylate Benzene The Gilman reagent The Stille reaction

  10. The Suzuki reaction

  11. One needs to consider an alternative if there is another functional group present in the compound

  12. Chemical Modification of Substituents of Benzene Reactions of alkyl substituents

  13. The resulting halide product can undergo a nucleophilic substitution reaction

  14. Remember that halo-substituted alkyl groups can also undergo E2 and E1 reactions (Section 9.8)

  15. Substitutions with double and triple bonds can undergo catalytic hydrogenation (Section 4.11 and 6.9)

  16. Oxidation of an alkyl group bonded to a benzene ring… Provided that a hydrogen is bonded to the benzylic carbon,

  17. The same reagent that oxidizes alkyl substituents will oxidize benzylic alcohols

  18. However, aldehydes or ketones can be generated if a milder oxidizing agent is used

  19. Reducing a Nitro Substituent

  20. It is possible to selectively reduce just one of the two nitro groups

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