| abstract |
Uaturated ketones of formulan n possessing two single or two double bonds in the positions indicated by the dotted lines (n = 1 or 2) are prepared by reacting, in the presence of a basic reagent, a dialdehyde of formulan n wherein the index n and the dotted lines have the above meaning with a diphosphonate of formulan n wherein R represents an alkyl radical. n Compounds of formula (I), which are new, are also useful perfuming and flavouring ingredients. |