Carbocation Rearrangements can be defined “as the movement of the carbocation from an unstable state to a more stable state by making use of different structural reorganizational shifts within the molecule”. Alkyl carbocation is a carbocation comprising of an alkyl group. They are the most common carbocation.
Carbocation Rearrangement occurs whenever the alcohols are converted into several carbocations and this phenomenon is termed as carbocation rearrangement. In simple carbocation comprises of +ve charge in a molecule that is connected to 3 more groups and holds a sextet. Carbocation rearrangement can be carried out to a reaction that does not involve alcohol. There are 2 types of carbocation rearrangements namely Alkyl and Hybrid Shift.
An alkyl shift occurs when a carbocation does not contain a hydrogen atom that is present on the adjacent carbon atom that is readily available for rearrangement. There are some cases where hybrid shift does not lead to a stable carbocation. For instance, consider the following case.
Suppose if alkyl group migrates there would be a chance for formation of tertiary carbocation that is more stable.
When a carbon attached to four carbons are present adjacent to secondary carbocation then there would be a possibility for the occurrence of alkyl shift.
This alkyl occurs when a carbon – carbon bond donates a pair of electrons to the empty p-orbital on the carbocation. It can occur potentially at any time when carbocation is formed.