8.5 Haloform Reaction

8.5 Haloform Reaction

  • When each of the compounds is treated with hydroxide, draw the enolate that would be generated.
    • Make sure you draw all resonance structures.
  • We learned how to make enolates in the previous section.
    • We will see what an enolate can do.
    • The reaction between an enolate and a halogen will be explored in this section.
    • The reactions between an enolate and other electrophiles will be explored in the following sections.
  • This enolate can be formed in the presence of br.
  • The enolate expels Br as a leaving group.
  • The reaction goes on.
    • The base is still present in the solution.
    • Another alpha proton can be removed with hydroxide.
  • The CH group has been converted into a CBr group.
  • You should be uncomfortable at this point.
  • This is a rare exception to the golden rule.
    • This is one of the rare cases where a C- can be stable enough for it to serve as a leaving group.
  • The loss of this leaving group is caused by the formation of the stable carbonyl group.
    • Even though it can leave, it is not the most stable anion on the planet.
    • It is not as stable as a carboxylate ion.
  • This forms a carboxylate anion.
    • This is the end of our mechanism.
  • Iodoform is a yellow solid.
    • This reaction can be used to investigate the identity of a compound.
    • If the compound is a methyl ketone, it will produce iodoform under these conditions.
  • The chemical test is a relic of the past.
    • It is still used in textbook problems.
    • An unknown compound tests positive for iodoform.
    • The problem begins when you are told that you have a drug.
    • You should know what this means if you see it in your textbook.
  • There is more use for this reaction.
    • It can be used to solve synthesis problems.
  • The haloform reaction is most efficient when the other side of the ketone has no protons.
  • This is a new example of a "cross-over" reaction.
    • In the previous chapter, we talked about how to convert ketones into carboxylic acid derivatives.
    • The process that we explored in this section can be used to make a carboxylic acid.
    • You should add this to your collection.
  • Draw a mechanism for the transformation in the previous Problem on a separate piece of paper.