Which of the following conversion represents Fries rearrangement?

• Correct answer
  A

  O-acylated phenol to C-acylated phenol
• B

  C-acylated phenol to O-acylated phenol
• C

  \(\mathrm{N}\)-acylated phenol to \(\mathrm{C}\)-acylated phenol
• D

  C-acylated phenol to \(\mathrm{N}\)-acylated phenol

Solution

Key Idea Fries rearrangement is a rearrangement of reaction of phenolic ester to a hydroxyl aryl ketone by catalysis of Lewis acid. From the given options, (a) represents Fries rearrangement, i.e. O-acylated phenol to C-acylated phenol. The reaction can be written as follows :

Hence, the correct answer is option: 'A'.