Novel .beta.-ketone compounds of the formula ##STR1## wherein R is a linear or branched alkyl of 4 to 10 carbon atoms optionally containing a double bond or an epoxy and optionally substituted with a branched or linear alkoxy of 1 to 3 carbon atoms, Z is selected from the group consisting of --CH=CH--, --CHOH--CH=CH--, ##STR2## and --OCH.sub.2 --, X is selected from the group consisting of hydrogen and methyl, Y is selected from the group consisting of linear and branched alkoxy of 1 to 5 carbon atoms and ##STR3## and R' and R" are linear or branched alkyl of 1 to 4 carbon atoms which are insecticides and their preparation.