The document discusses several rearrangement reactions, including those that involve migration to electron deficient carbons, nitrogens, and oxygens. Specifically, it mentions that phenyl groups migrate more readily than other groups to carbon, describes the pinacole-pinacolone and benzilic acid rearrangements which involve carbon migration, and the Hofmann rearrangement where migration occurs to nitrogen when a carboxylic acid amide is treated with bromine under basic conditions. It also references the Baeyer-Villiger oxidation where migration happens to oxygen.

1. 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

2. Pinacole-Pinacolone Rearrangement

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

4. 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.

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