Chemico-microbial syntheses of Japanese beetle and mosquito oviposition pheromones
✍ Scribed by Sowmianarayanan Ramaswamy; Allan C. Oehlschlager
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- French
- Weight
- 633 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0040-4020
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✦ Synopsis
Japanese beetle and mosquito oviposition attractant pheromones have been synthesized from a common chiral precursor derived from baker's yeast reduction.
In this report we describe the chemico-microbial syntheses of two insect pheromones that possess chiral 7 and 8 lactones. 1 (R)-(-)-(Z)-5-tetradecenolide, 1, the female produced sex pheromone of the economically important Japanese beetle, Popiliajaponica, 2,3 is required to be nearly optically pure to exhibit full activity. The presence of as little as 5% of the (S,Z) isomer lowers the attractancy of the (R,Z) isomer to 30% of the optically pure material. 4a There are a number of racemic and chiral syntheses of 1 reported. 4ak 6(S)-Acetoxy-5(R)-hexadecanolide, 2, is the major component of the apical droplets that form on the eggs of the mosquito Cu/ex pipens fatigans. 5 The substance acts as an oviposition pheromone attracting gravid females of the same mosquito species and inducing them to oviposito The natural material was shown to be the 5(R),6(S) isomer by comparison with synthetic material.6 There are many chiral syntheses of this lactone starting from the chiral pool.7a'j 1 2
Scrutiny of these two molecules shows they share an R-configuration at the alkoxy center and an adjacent oxidized or unsaturated carbon. These common elements make it possible to develop syntheses from the same chiral precursor. One obvious route to the chiral precursor is baker's yeast (Saccharomyces cerevisiae) reduction of appropriate ketones which follows Prelog's rule. s Ketones containing adjacent primary hydroxyl groups undergo identical reduction 9 at substantially accelerated rates suggesting chelation involving the hydroxyl group at the active site. Starting with an appropriately substituted ketol, it is possible to elaborate the yeast reductionderived diol into either 1 or 2..Initially, our synthesis of 1 started with the aldehyde 3 obtained by a