Rearrangement to Electron Deficient Carbon

• Migratory aptitude : Ph> R, H

• The migratory aptitude of phenyl group increases with electron donating groups

Generation of Carbonium ion

Pinacole-Pinacolone Rearrangement

• Benzilic acid rearrangement-Diketones undergo a rearrangement when treated with hydroxide ion, giving-hydroxyacids.

Rearrangement to Electron-deficient Nitrogen

• Hofmann rearrangement- A carboxylic acid amide is treated with sodium hypobromite, or bromine in alkali. The N-bromo-amide is formed and reacts with the base to give its conjugate base within which rearrangement occurs.

Migration to Electron-Deficient Oxygen- The Baeyer-Villiger Oxidation