The present invention relates to the perfumery industry. It concerns more particularly a .beta.-.gamma. unsaturated hindered ketone of formula ##STR00001## wherein R represents, simultaneously or independently, a C.sub.1 to C.sub.4 linear or branched alkyl group, and in the form of any one of its isomers, i.e. optical isomers or diastereoisomers, or of a mixture thereof. The use of the compound as a perfuming ingredient, as well as the perfumed articles or perfuming compositions that contain as an active ingredient a compound of formula (I), are also embodiments of the invention.