Define :

When an α-diazo ketone is decomposed thermally photo-chemically or catalytically and converted to ketone by removal of dinitrogen, it is called wolf rearrangement.

The reaction was given by Ludwing Wolf in 1902.

Reaction:

When ketene is formed it acts as an intermediate for forming acid Ester and Amide.

Mechanism of Wolf Rearrangement:

Wolf rearrangement shows a concerted mechanism (single step) or also follows a stepwise mechanism which is as follows;

Concerted Mechanism:

Stepwise Mechanism:

Step(1), Formation of acid halide:

Step(2), Formation of carbene:

Step(3), Formation of ketene:

Application of Wolf Rearrangement:

The application of wolf rearrangement is as follows;

• Ring Contraction Reaction
• Higher Homologous
• Formation of oxygen (Photochemical Reaction)

(1)Ring Contraction Reaction:

Wolf rearrangement shows ring contraction reaction as follows;

 

Mechanism of ring contraction reaction:

Higher Homologous:

By wolf rearrangement we increase carbon chain length.

Reaction :

 

Here we use selective oxidizing agent which is pyridinium chlorochromate and manganese dioxide. Thus;

Mechanism:

Formation of Oxyrene

It is also known as photochemical reaction .

3 membered ring is relatively highly unstable and break to form carbene and then ketene formation

Mechanism :

We also form carboxylic acid, ester and amine by different starting material