Pheromones ipsenol

In some insects, fatty acid elongation followed by decarboxylation produces the hydrocarbon pheromones, and these include examples of lepidopterans (Jurenka), dipterans [71], the German cockroach [72a] (see Fig. 6) and the social insects [73]. More recent work in bark beetles has shown that Ips and Dendroctonus spp. produce their monoterpenoid-derived pheromones ipsenol, ipsdienol and frontalin by modifications of... 

A number of new and asymmetric syntheses of (S)-(-)-ipsenol (34) and (S)-(+)-ipsdienol (35), the pheromone of Ips bark beetles, were reported. Scheme 49 summarizes the synthesis of ipsenol by Riedeker and Steiner [75], which enabled them to prepare 56 g of (S)-34. They employed chiral auxiliary B derived from D-glucose. 

Attempts to investigate boll weevil (Anthonomus grandis) pheromone biosynthesis have identified isomerization, dehydration, and oxidation of the pheromone alcohols, and anticipated allylic oxidation of myrcene and limonene, but no evidence for the cyclization of acyclic precursors. The aggregation pheromones of bark beetles have been reviewed. Ips calligraphus responds to ipsdienol only in the presence of the c/5-verbenol (32) large additional concentrations of the enantiomer (l/ ,4i ,5/ )-(32) reduce beetle response. 5-(-)-Ipsenol, the pheromone of Ips grandicollis, increases the response of /. avulsus to its own pheromone ipsdienol. ... 

As is indicated in Fig. 22-3, the same intermediate cation can yield a variety of end products. For example, pure geranyl diphosphate pinene cyclase catalyzes formation of several other terpenes in addition to a-pinene.89 Another aspect of terpene synthesis is that insects may convert a plant terpene into new compounds for their own use. For example, myrcene, which is present in pine trees, is converted by bark beetles to ipsenol (Fig. 22-3), a compound that acts as an aggregation pheromone.90... 

Seybold S. J., Quilici D. R., Tillman J. A., Vanderwel D., Wood D. L. and Blomquist G. J. (1995) De novo biosynthesis of the aggregation pheromone components ipsenol and ipsdienol by the pine bark beetles Ips paraconfusus Lanier and Ipspini (Say) (Coleoptera Scolytidae). Proc. Natl. Acad. Sci. USA 92, 8393-8397. 

Figure 6.9 Examples of pheromone components of bark beetles (Scolytidae) and ambrosia beetles (Scolytidae and Platypodidae) classified by likely biosynthetic origin (based on Francke and Schulz, 1999). (A) References for identification and/or behavioral activity of isoprenoid pheromone compounds are as follows-. 2-methyl-3-buten-2-ol (Bakke efa/., 1977 Giesen etal., 1984 Klimetzek etal., 1989a Lanne etal., 1989), 3-methyl-3-buten-1-ol (Stoakley etal., 1978 Bowers and Borden, 1990 Bowers etal, 1991 Zhang efa/., 2000), 3-methyl-1-butanol (Renw ick etal, 1977), 3-hydroxy-3-methylbutan-2-one (Francke and Heeman, 1974 Francke etal 1974), ipsenol and ipsdienol...

Figure 6.11 Biosyntheses of isoprenoid pheromone components by bark and ambrosia beetles from host conifer monoterpenes. (A) Conversion by the male California fivespined ips, Ips paraconfusus Lanier (Coleoptera Scolytidae), of myrcene from the xylem and phloem oleoresin of ponderosa pine, Pinus ponderosa Laws., to (4S)-(+)-ipsdienol and (4S)-(-)-ipsenol, components of the aggregation pheromone (Hendry et al., 1980). (B) Conversion by male and female I. paraconfusus of (1 S,5S)-(-)-a-pinene (2,6,6-trimethyl-bicyclo[3.1,1]hept-2-ene) from the xylem and phloem oleoresin of P. ponderosa to (1 S,2S,5S)-(+)-c/s-verbenol (c/s-4,6,6-trimethyl-bicyclo[3.1,1]hept-3-en-2-ol), an aggregation pheromone synergist and of (1 R,5R)-(+)-a-pinene to (1 fl,2S,5fl)-(+)-frans-verbenol (frans-4,6,6-trimethyl-bicyclo[3.1,1]hept-3-en-2-ol), a compound of unknown behavioral activity for /. paraconfusus. Male and female western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera Scolytidae), convert (1 S,5S)-(-)-a-pinene to (1S,2ft,5S)-(-)-frans-verbenol, an aggregation pheromone interruptant and (1R,5R)-(+)-a-pinene to (1 R,2S,5R)-(+)-frans-verbenol, a compound of...

Some early and obvious questions about bark beetle pheromone components concerned their origins are they synthesized de novo from acetate or derived from plant precursor molecules And are the biochemical reactions performed by insect tissues or symbiotic bacteria Ipsdienol and ipsenol are clearly monoterpenoid alcohols. Since de novo monoterpenoid biosynthesis was unprecedented in the Metazoa before 1995, and monoterpenes are produced by host trees, it seemed logical that monoterpenoid pheromone components were derived from ingested plant precursor molecules (reviewed in Vanderwel and... 

Birch M. C. and Light D. M. (1977) Inhibition of the attractant pheromone response in Ipspini and Ipsparaconfusus (Coleoptera Scolytidae) field evaluation of ipsenol and linalool. J. Chem. Ecol. 3, 257-267. 

Proline-catalyzed direct aldol reactions have also been employed in the context of natural products synthesis, as is illustrated in the synthesis of the bark beetle pheromone (S)-ipsenol of Scheme 4 [16d],... 

Addition of an allylsilane to acid chlorides has been used to synthesize ipsenol and ipsdienol, principal components of the aggregation pheromone of the bark beetle Ips paraconfusus (Figure Si6.3). It is of note that the allylsilane used in these syntheses is a versatile source of the isoprene unit. 

The procedure of exp. 12 exemplifies the regiospecific reaction of dilithiated isopropenyl acetylene with carbonyl compounds. This example is significant in that the coupling product is a precursor of an aggregation pheromone of the baric beetle treatment with activated zinc powder in ethanol gives ipsenol H2C=CHC(=CH2)CH2CH(OH)CH(CH3)2 in almost quantitative yield. [46]... 

Scolytidae. The worldwide ranges of bark beetles have made them ideal candidates for research directed toward the isolation and identification of pheromones that can be used for population monitoring and regulation. A decade ago, the aggregative pheromone liberated by males of Ips paraconfusus (=confusus) was identified as a mixture of (-)-2-methyl-6-methylene-7-octen-4-ol (ipsenol) (XVI), (+)-cis-verbenol (XVII), and (+)-2-methyl-6-methylene-2,7-octadien-4-ol (ipsdienol) (XVIII)... 

Most asymmetric syntheses require rather more than one or two steps from chiral pool constituents. Male bark beetles of the genus Ips produce a pheromone that is a mixture of several enantiomerically pure compounds. One is a simple diene alcohol (S)-(-)-ipsenol. Japanese chemists in the 1970s noted the similarity of part of the structure of ipsenol (in black) to the widely available amino acid (S)-leucine and decided to exploit this in a chiral pool synthesis, using the stereogenic centre (green ring) of leucine to provide the stereogenic centre of ipsenol. 

The faecal pellets of the bark beetle Ips paraconfusus which had fed on the phloem of Pinus ponderosa contained large quantities of the aggregation pheromones cis-verbenol (24), ipsenol (25), and ipsdienol (26). The pheromones originate in the hindgut, but, although there is a precursor-product correlation between a-pinene or myrcene from the phloem and the pheromone terpenoids, the biosynthetic site is unclear. The demonstration68 of the conversion of a-pinene into cis- and trans-verbenol (27) by Bacillus cereus found in the gut of I. paraconfusus has led to the... 

Bark beetles are of great economic importance, which is one of the reasons more research has been done on the pheromones of the Scolytidae than on those of any other family of Coleoptera. Their pheromone systems also seem to be typical of the Coleoptera in that while there is considerable diversity in pheromone structure within this family, there also seems to be a pattern of structures, particularly within a genus. The first pheromone identified from a coleopterous species was from Ips paraconfusus Lanier (then I. confusus) by Silverstein et al. (13). Three compounds — ipsenol (I), ipsdienol (II), and cis-verbenol (III)... 

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