4-(2'-norbornyl)-2-butanones characterized by the structural formula ##SPC1## Wherein R.sup.1 represents hydrogen or methyl, and R represents hydrogen or a lower alkyl group are prepared by a crossed aldol condensation of 5-norbornene-2-carboxaldehyde or norbornane-2-carboxaldehyde with methyl ketones in a basic medium followed by a subsequent dehydration of the aldol formed to prepare the 3-buten-2-ones which are subsequently hydrogenated. The compounds have very pleasant, strong and long lasting woody odors and are useful as compounds in fragrance compositions.