Improved Preparation of Carpophilus freemani Aggregation Pheromone

Abstract

The synthetic route to (2E,4E,6E)-5-ethyl-3-methyl-2,4,6-nonatriene, the aggregation pheromone of the Freeman sap beetle, Carpophilus freemani Dobson (Coleoptera: Nitidulidae), has been improved in terms of 6E isomer selectivity by the use of tetra-n-propyltriphenylphosphonium bromide in the final Wittig reaction. Separation of the 6E-isomer from undesired 6Z-isomer can be accomplished on a preparative scale by HPLC using a silica column with hexane as the elution solvent. This chromatographic method was also used to purify the aggregation pheromone of the dusky sap beetle, Carpophilus lugubris Murray.

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