91Ó°ÊÓ

Reactions, where the reactants get rearranged to generate structural isomers are referred as rearrangement reactions. Rearrangement reactions can be of various kinds, and one among them is the sigmatropic rearrangement.

Sigmatropic rearrangement can occur in the presence of heat conditions or light conditions. Claisen rearrangement is a [3,3] sigmatropic rearrangement that is frequently employed in organic reactions.

a. The skeletal structure of compound a can be given as:

Skeletal structure of compound a

The product formed by the sigmatropic rearrangement of compound a is a carbonyl compound and can be given as:

Product formed by the [3,3] sigmatropic rearrangement of compound a

b. The skeletal structure of compound b can be given as:

Skeletal structure of compound b

Compound b undergoes [3,3] sigmatropic rearrangement to form a carbonyl compound. The product formed by the sigmatropic rearrangement of compound b can be given as:

Product formed by the [3,3] sigmatropic rearrangement of compound b