ORGANIC CHEMISTRY SELECT

Wagner–Meerwein rearrangement is a class of carbocation 1,2-rearrangement reactions in which a hydrogen, alkyl or aryl group migrates from one carbon to a neighboring carbon. ref1,2

Several reviews have been published.ref 3-7

The rearrangement was first discovered in bicyclic terpenes for example the conversion of isoborneol to camphene ref8:

Isoborneol Camphene Conversion

The story of the rearrangement reveals that many scientists were puzzled with this and related reactions and its close relationship to the discovery of carbocations as intermediates.ref 9

In a simple demonstration reaction of 1,4-dimethoxybenzene with either 2-methyl-2-butanol or 3-methyl-2-butanol in sulfuric acid and acetic acid yields the same disubstituted product,ref 10  the latter via a hydride shift of the cationic intermediate:

Carbocation rearrangement Polito 2010

Currently, there are works relating to the use of skeletal rearrangement in the synthesis of bridged azaheterocycles. These data are summarized in ref11

Some examples of Wagner-Meerwein rearrangement in heterocyclic series

Plausible mechanisms of the Wagner-Meerwein rearrangement of diepoxyisoindoles:

Plausible mechanisms of the Wagner-Meerwein rearrangement of diepoxyisoindoles

The related Nametkin rearrangement named after sergey nametkin involves the rearrangement of methyl groups in certain terpenes. In some cases the reaction type is also called a retropinacol rearrangement 

  1.  Wagner, G. 

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