Wolff Rearrangement

Wolff Rearrangement Definition:

Treatment of an acid halide with diazomethane (CH2N2) followed by heating leads to the formation of a ketene which can be further used in many synthetic reactions.

Wolff Rearrangement Explained:

The Wolff rearrangement is a reaction in which an α-diazocarbonyl compound is converted into a ketene by the loss of dinitrogen with accompanying 1,2-rearrangement.

This reaction contains two possible reaction mechanisms. It is not yet clear which of these mechanisms is correct. Common for both mechanisms is the production of diazo ketone that will act as the reactant in the Wolff rearrangement. And diazo ketone forms in the reaction between an acid chloride and diazomethane.

One of the resonance structure of diazomethane attacks the carbonyl carbon, the π breaks and the