A convenient two-step homologation of bothaliphatic and aromatic ketones to the corresponding carboxylic acid has been developed. First ketones were converted to epoxynitriles with the Darzens reaction. Second,a Lewis acid mediated rearrangement of these epoxynitrileswith lithium bromide was achieved to give homologatedsecondary alkanoic acids (as well as aryl-alkanoic) in goodyields. The mechanism and the scope of the rearrangementreaction were investigated. This strategy constitutes a two-step homologation of ketones to secondary carboxylic acids.
