Wagner-Meerwein Rearrangement
Wagner-Meerwein rearrangements are associated with 1° carbenium ions rearranging to more stable 2° and 3° carbenium ion via the 1,2-shift of an adjacent alkyl or aryl function.

Wagner-Meerwein rearrangements can be used to (i) contract or expand non-aromatic rings or (ii) make sterically crowded 4° alkyl centres. Rearrangements are stereospecific.

For more information look in the Chemogenesis webbook sections on rearrangement reactions and pericyclic reactions.