Olive fly pheromone

Finally, oxidative cyclization (HgO, I2, hiA of tqjpropriately substituted alcoholic ethers formed the basis of Kay s stereoselective syntheses of both 4-hydroxy-l,7-dioxaspiro[S.S]undecane, an olive fly pheromone component, and ( )-talaromycin B (equations 4 and 5). More recently, Danishefsky et at have further extended the scope of this spiroketal-forming reactitm in their elegant total synthesis of avermectin Ai (equation 6). ... 

Both enantiomers of 3-hydroxy-l,7-dioxaspiro[5.5]undecane (471), the minor component of the olive fly pheromone, can be synthesized from (5)-malic acid via acetonide 454b (Scheme 66) [120]. The initial carbon skeleton is constructed by sequential alkylation of 341 with 454b and then EE-protected 4-iodobutanol. Copper-mediated hydrolysis of the dithiepin ring affords a complex mixture of products, two of which, (3aS, 65)-471 and 472, are isolated in 33% and 18% yields respectively. 

Spiro compounds, in which the stereogenic centre is at the fusion of two rings, can also be chiral, as in the example of the olive-fly pheromone (27). 

Consider general approaches to the synthesis of (22), the sex pheromone of the olive fly, a serious pest of... 

Synthesis of Haptens and the development of an enzyme-linked immunoassay (ELISA) for the olive fruit fly pheromone, Bactrocera oleae has been reported. 

Don t suppose that the females always do all the work both male and female olive flies produce pheromones that attract the other sex. The remarkable thing is that one mirror image of the molecule attracts the males while the other attracts the females ... 

Baker, R., Francke, W., Herbert, R., Howse, P.E., Jones, O.T., and Reith, W. 1980. Identification and synthesis of the major sex pheromone of the olive fly (Dacus oleae). Journal of the Chemical Society, Chemical Communications, 2 52-3. 

Let s start with the simplest example, with R = H (a pheromone of the olive fly). Once you have drawn one ring in its chair conformation, there are three ways of attaching the other ring, shown here. If you think they all look the same, consider the orientation of each C-O bond with respect to the ring that it is not part of you can have each C-O axial or equatorial, and there are three possible arrangements (three conformations). 

In particular, the importance of chirality in diverse pheromone systems has been reviewed recently (Mori, 1998). For example, olive fruit flies (Bactrocera oleae) emit racemic 2 the males detect the R enantiomer, while females detect the S (Haniotakis et al., 1986). The sex pheromone of the Osaka beetle (Anomala osakana) is 4a, while the closely related Japanese beetle (Popilia japonica) uses 4b (Table 16.1). Interestingly, 4a is a powerful behavioral antagonist in P. japonica (Tumlinson et al., 1977). The hemlock looper, Lambdina fiscellaria, responds only to (5R, 1 S)-5,I I -dimethylheptadecane. The enantiomer or the R/R or S/S diastereomers do not elicit electrophysiological or behavioral responses (Li et al., 1993). Table 16.1 gives an overview of those species where proteins from the pheromone olfactory system have been identified. 

Two important spiroketals, such as l,7-dioxaspiro[5.6]undecane (29a), the major component of the olive fruit fly (Dacus oleae) sex pheromone (Baker et ah, 1980 Fanelli et ah, 1983), and ( )-2-methyl-l,7-dioxaspiro[5.6]dodecane (29b), a component of pheromone of Andrena haemorrhoa (Bergstroem et al., 1981 Katsurada and Mori, 1984), have been prepared in a cascade process from polyfunctionalized nitroalkanes (26) (Ballini and Petrini, 1992). 

The olive fmit fly (Bactrocera oleae) is the major pest of olive trees in Mediterranean countries such as Greece, Israel, Italy and Spain. In 1980 Baker, Francke and their respective coworkers isolated and identified the female-produced sex pheromone of B. oleae as l,7-dioxaspiro[5.5]undecane (116, Figure 4.74), and named it olean.132 Its racemate ( )-116 can readily be synthesized as shown in Figure 4.74, and is pheromonally active.132... 

The enantiomers of olean were bioassayed in Greece by Haniotakis el a/.136 Surprisingly, (R)-116 was active against males, whereas (S)-116 was active against females. GC analysis on a chiral stationary phase of natural olean by Schurig revealed it to be ( )-116.136 Thus, the female-produced sex pheromone activates male olive fruit flies and the female herself. This is a very unusual stereochemistry-pheromone activity relationship, and is beyond our imagination. 

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