Favorskii Reaction

The rearrangement of cyclopropanones, often obtained as intermediates from the base-catalyzed reaction of α-halo ketones, leading to carboxylic acids and derivatives.

Mechanism of the Favorskii Reaction

Esters are obtained if alkoxide bases are used:

A direct conversion from α-halo ketones is possible:

Ring-contraction:

source:www.organic-chemistry.org