Benzylic oxidation

  
   
 

Treatment of an alkylbenzene with potassium permanganate results in oxidation to give the corresponding benzoic acid.

Mechanism

  
  The mechanism is very complex and it is not necessary to know it in detail.  
     
 
  • Potassium permanganate oxidizes the benzylic position of the benzene ring probably through a radical process.
  • The presence of an acid protonates the carboxylate to give the corresponding carboxylic acid.