2007 Annual Report 1a.Objectives (from AD-416) The objective of this cooperative research project is to synthesize biologically active organic compounds and evaluate their activity as elicitors of plant volatiles and/or as mediators of plant-insect interactions. 1b.Approach (from AD-416) Organize compounds isolated from insects or other sources and identified as having biological activity as plant volatile elicitors or in mediating insect behavior will be synthesized and the synthetic compounds will be tested in biological assays to determine their activity and compare their biological activity to naturally produced compounds. 3.Progress Report This report serves to document research conducted under a specific cooperative agreement between ARS and the Chemistry Department, Virginia Military Institute (VMI). Additional details of research can be found in the report for the in house associated project 6615-22430-002-00D, Chemistry and Biochemistry of Insect Behavior, Physiology, and Ecology. The major effort has been to develop a synthesis of the grasshopper elicitor of plant volatile release, “califeran A”. There are two difficult parts in this compound, the E double bond at C-6 and the chiral carbon at C-2. Since beginning with a chiral precursor is more desirable that trying to oxidize C-2 of an ester asymmetrically, a variation of this methodology is to utilize a different chiral precursor, ethyl glycidate which can be prepared from the amino acid serine. This preparation has been reported in Organic Synthesis. Serine is available in either enantiomer. A great deal of the work that has been done this year has been an intensive literature search regarding the possible nucleophiles that could be added to ethyl glycidate. Some of the best candidates are alkyl zinc reagents catalysed by various other metals. After some initial trials with nucleophiles derived from bromoalkanes, nucleophiles have been made from the dienol and its bromide. A great deal of time was spent in designing a route that would be cleaner, or at least make it possible to separate the product from much smaller side products and starting materials. Additionally we would like to be able to control the absolute configuration at C-2. We decided that the best way to do this will be to start with a chiral precursor. Our initial attempts with a synthon based on S-malic acid were not as successful as we would have liked, and a route based on epoxide opening is under study as of this writing. Progress is monitored through email and telephone discussions on a monthly basis between the USDA and the Virginia Military Academy collaborator and by quarterly reports from the collaborator.