Stereospecific syntheses of sex pheromones of the californian red scale and white peach scale (Homoptera: Diaspididae) based on 1,4-cis-hydrogenation of dienes

Article abstract of DOI:10.1007/BF00707233

Stereospecific syntheses of (+/-)-3-methyl-6-isopropenyl-3(Z),9-decadien-1-yl acetate and (+/-)-3,9-dimethyl-6-isopropenyl-3(Z),9-decadien-1-yl propionate (the Racemoc forms of the pheromones of the scales Aonidiella aurantii and Pseudaulascaspis pentagona) with a geometrical purity of the (Z)-trisubstituted double bond not lower than 99percent were performed.The key step in both syntheses was the 1,4-cis-hydrogenation of the corresponding ethyl 3-methyl-6-(1,1-ethylenedioxyethyl)-2,4,9-decatrienoates catalyzed with chromium carbonyl complexes.These 2,4-dienes were obtained in five conventional steps including the alkylation of ethyl acetoacetate by the appropriate 1-bromo-3-butenes and the Horner-Emmons olefination of the corresponding α-branched aldehydes. - Keywords: (+/-)-3-methyl-6-isopropenyl-3(Z),9-decadien-1-yl acetate, (+/-)-3,9-dimethyl-6-isopropenyl-3(Z),9-decadien-1-yl propionate, synthesis, aldehydoketals, ethyl 2,4-alkadienoates, 1,4-cis-hydrogenation, the Horner-Emmons olefination, ethyl acetoacetate, alkylation, arene chromium tricarbonyl complexes