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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Invasive Insect Biocontrol & Behavior Laboratory » Research » Publications at this Location » Publication #267026
Title: Synthetic studies toward 7-epi-sesquithujene, bicyclic sesquiterpene antennally active to emerald ash borer

Author
item Khrimian, Ashot
item Cosse, Allard

Submitted to: Journal of Natural Products
Publication Type: Abstract Only
Publication Acceptance Date: 5/6/2011
Publication Date: 5/16/2011
Citation: Khrimian, A., Cosse, A.A. 2011. Synthetic studies toward 7-epi-sesquithujene, bicyclic sesquiterpene antennally active to emerald ash borer. Journal of Natural Products. 74:1414-1420.

Interpretive Summary:

Technical Abstract: Emerald ash borer, Agrilus planipennis, is an invasive beetle that has been causing extensive mortality of ash trees since arriving in North America in 2002. 7-epi-Sesquithujene (1) is produced by stressed ash and elicits a strong EAD response on the emerald ash borer antennae. In the course of making a synthetic 7-epi-sesquithujene for field studies, we found that this compound was drawn in literature incorrectly and ultimately determined its absolute configuration as 4S,6S,7R. We synthesized 7-epi-sesquithujene as well as other diastereomers from commercially available (R)- and (S)-citronellals. The synthesis was conducted in a straightforward approach, circumventing expensive chiral catalysts and reagents. Even tough it produced 7-epi-sesquithujene in a mixture, the three accompanying diastereomers were found inactive in GC-EAD studies. While conducting L-Selectride reduction of intermediate bicyclic ketones (2), we discovered an unusual stereochemistry that remarkably helped to make individual diastereomers and develop a chiral GC method for separation of all four.