Two-Carbon Ring-Enlargement of Cyclic 1,3-Diketones to Cyclic 1,5-Diketones

3-Hydroxy-3-vinylcycloalkanones, which were prepared from the corresponding cyclic 1,3-diketories by mono-vinylation, were rearranged to two-carbon ring enlarged cyclic 1,5-diketones by treatment with a catalytic amount of potassium tert-butoxide.