Wagner-Meerwein rearrangement synthetic utility

The carbonium ion may also be formed from an alkene or alcohol. The carbonium ion formed from any of these starting materials is particularly prone to rearrangement reactions. These are called Wagner-Meerwein rearrangements, and severely limit the synthetic utility of this reaction to form simple alkyl substituted aromatic compounds. The tendency to rearrange may be reduced if the acyl derivative is used instead. This modification is called the Friedel-Crafts acylation reaction, and it has the further advantage that normally only monoacylation occurs, instead of the polyalkylation that happens using the simple Friedel-Crafts reaction. 

Since its discovery in the context of the reactions of the monoterpenoids, examples of the rearrangement have been found in many other systems. Therefore, for the purposes of this chapter, which is concerned with the synthetic utility of the Wagner-Meerwein type of rearrangement, some reactions involving substituents migrating will be included as well as examples of skeletal rearrangement in polycyclic systems. 

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