2,3-sigmatropic Rearrangement

2,3-sigmatropic Rearrangement

2,3-Sigmatropic rearrangements are a type of sigmatropic rearrangements and can be classified into two types. Rearrangements of allylic sulfoxides, amine oxides, selenoxides are neutral. Rearrangements of carbanions of allyl ethers are anionic. The general scheme for this kind of rearrangement is:

Atom Y may be sulfur, selenium, or nitrogen. If Y is nitrogen, the reaction is referred to as the Sommelet–Hauser rearrangement; if Y is oxygen, then it is called a 2,3-Wittig rearrangement (not to be confused with the well-known Wittig reaction, which involves a phosphonium ylide). If Y is sulphur, the product can be treated with a thiophile to generate an allylic alcohol in what is known as the Mislow–Evans rearrangement.

A -rearrangement may result in carbon-carbon bond formation. It can also be used as a ring-expansion reaction.