New process for the preparation of cyclic ketones possessing interesting organoleptic properties and including methyl 2-(cis-pent-2-enyl)-3-oxo-cyclopentylacetate and 3-methyl-2-(cis-pent-2-enyl)-cyclopent-2-enone, better known in the perfume industry as cis-methyl jasmonate and cis-jasmone respectively.