Here it is.
The pinacol rearrangement is the acid-catalyzed rearrangement of a 1,2-diol to a ketone.
The name of the rearrangement comes from the rearrangement of pinacol (2,3-dimethylbutane-1,2-diol) to pinacolone (2,2-dimethylbutanone).
There are several steps in the rearrangement.
Step 1. Protonation
The acid protonates an
Step 2. Loss of water
A molecule of water leaves, forming a 3° carbocation.
Step 3. 1,2-Methyl shift
A methyl group migrates to the carbocation, forming a resonance stabilized protonated carbonyl group.
Step 4. Deprotonation
A water molecule removes the proton from the carbonyl oxygen, forming the product, pinacolone.