Submitted to: Synthetic Communications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2000
Publication Date: N/A
Interpretive Summary: Due to customer concerns about the use of broad-spectrum pesticides and their effect on the environment, we are developing pest control strategies requiring the use of less pesticide. Sap beetles of the genus Carpophilus are pests of corn that can introduce and transmit damaging fungi from ear to ear. Male sap beetles produce a chemical substance, termed an aggregation pheromone, that selectively attracts male and female members of its own species. We can use pheromone-baited traps in fields to monitor for the presence and numbers of specific insect pests and thus precisely time the use of pesticide sprays. Commercialization of pheromone baits has been impeded by the lack of a robust synthetic pathway leading to the compounds. We have improved a critical step of the process and the potential use of these pheromones in agriculture is more likely as a result of our research efforts.
Technical Abstract: The E-isomer selectivity of the Horner-Wadsworth-Emmons olefination of aldehydes to form alpha-methyl- or alpha-ethyl- alpha,beta-unsaturated esters has been improved by using Lithium tert-butoxide as the base, triethyl-2-phosphonopropionate or treithyl-2-phosphonobutyrate as the phosphonate, an aldehyde, and hexane as the reaction solvent. Greater E-isomer selectivity was observed in the formation of alpha-methyl-alpha,beta-unsaturated esters than alpha-ethyl-alpha,beta-unsaturated esters. These compounds are useful intermediates for the synthesis of insect pheromones and natural products.