L14 - Carbonyl Chemistry withOUT leaving groups

• Reactions of aldehydes/ketones with water

  
  

  (what's the mechanism? What does it produce?)

  No leaving group!

  
  

  Produces hydrate via tetrahedral intermediate and proton transfer

  
• If starting material is more reactive, where does equilibrium lie?

  To the right - so more product is produced
• Ring strain - how does it affect the minor/major product?

  The carbocation wants to have a bond angle of 60 degrees, but if sp2 it's actually 120 so this is the minor product. If water is added, the major product formed is sp3 so 109.5, close to 60 and so more stable

  
• Adding alcohol to an aldehyde/ketone

  
  

  (what's required? what's the product?)

  - acid catalyst eg HCl

  - alkyl hemi ketal / alkyl hemi acetal

  
• Reactions with amines

  
  

  (what's the product?)

  Amines more nucleophilic than water/alcohols

  
  

  Alkyl hemi aminal

  
• Reaction with imines


  anything you can apply to C=o, you can apply to C=N

  
• What are the structures of enamine and iminium?

  
  

  How are they formed?

  
• Epimerisation


  where only one stereogenic centre changes