Scolytus multistriatus pheromone

Sn2 Reactions with epoxides and aziridines are also synthetically useful. An example of epoxide cleavage with an organocopper reagent with sp carbon moieties is the enantioselective synthesis of (3S, 4S)-4-methyl-3-heptanol (53), an elm bark beetle (Scolytus multistriatus) pheromone [42]. The chiral epoxy oxazolidine 51 [43], prepared from (R)-phenylglycinol, reacted with a propylmagnesium bromide-derived cuprate at —70 °C to afford the oxazolidine 52 in 74% yield (Scheme 9.12). Compound 52 was converted into the target molecular 53 by conventional procedures. 

Lanier G. N., Gore W. E., Pearce G. T., Peacock J. W. and Silverstein R. M. (1977) Response of the European elm bark beetle, Scolytus multistriatus (Coleoptera Scolytidae) to isomers and components of its pheromone. J. Chem. Ecol. 3, 1-8. 

Mori K. (1974) Synthesis of (15 2R 45 55)-(-)-a-multistnatin the pheromone in the smaller European elm bark beetle, Scolytus multistriatus. Tetrahedron 32, 1979-1981. 

S, 4S)-4-Methylheptan-3-ol is a component of the aggregation pheromone of the elm bark beetle Scolytus multistriatus. It is readily synthesized from the (s) pinanediol ester of propylboronic acid as shown in Figure B6.2. 

The terpenoid-exocrine theme emphasized by scolytid beetles was again evident when the chemical constitution of the secondary attractant for the smaller European elm bark beetle, Scolytus multistriatus, was elucidated. The aggregation pheromone was identified as a mixture of (-)-4-methyl-3-heptanol, 2,4-dimethyl-5-ethyl-6,8-dioxabicyclo [3.2.1]octane (multistriatin) (XXII), and (-)-a-cubebene (XXIII), a host-derived synergist (70). All three compounds are required for the maximum attraction of beetles. The inactive diastereomers of 4-methyl-3-heptanol and multistriatin did not inhibit the responses of airborne beetles. 

Such a sequence has been successfully used115 for the synthesis of 4-methyl-3-heptanol, the major constituent of the aggregation pheromone of the elm bark beetle (Scolytus multistriatus Marsham)117 and zir-butyM-methyltetrahydro-2-furanone118 known as quercus lactone or oak lactone. ... 

Application of the preceding strategy to multistriatin synthesis (Scheme 11.26) started with compound 7, which was deoxygenated at C3 and further elaborated to ketone 106 [49]. Wittig methylenation provided 107, and subsequent double bond reduction using Wilkinson s catalyst afforded the dimethylated compound 34 [93]. Further manipulation yielded a-multistriatin 108, the pheromone of Scolytus multistriatus. Other syntheses of this pheromon from sugars have been reported [48,94,95]. 

Bark beetles. Insects related to the weevils that bore into the wood and bark of trees and often cause extreme economic damage to forests. Many species live in symbiosis with fungi the elm bark beetle Scolytus multistriatus transmits the feared elm tree disease caused by the fungus Ceratocystis ulmi. Some B. species are controlled by the application of synthetic pheromones in trap devices, that contain combinations of pheromones with synthetic insecticides see also bre-vicomin, chalcogran, conophthorin, frontalin, ipsdienol, lineatin, multistriatin, pityol, sulcatol, seudenol. 

Enantiomeric composition of a pheromone is instrumental with respect to the behaviour mediating capacity of the signal. This especially stands for bark beetles (Coleoptera Curculionidae, Scolytinae) where even different populations of the same species employ pheromone of different enantiomeric composition (Seybold, 1993 Miller et al., 1996). Enantioselective production of, and response to pheromones has been demonstrated in many species of Scolytinae subfamily (Birch, 1984 Borden, 1985 Byers, 1989). Electrophysiological studies have revealed that species such as Ips pini Say, 1. typographus (L.), I. paraconfusus Lanier, Scolytus multistriatus (Marsham), S. scolytus (F.) and Trypodendron lineatum (Olivier) and many others have olfactory receptor cells specific to optical isomers of aggregation pheromones (Mustaparta et al., 1980,1984 Wadhams et al., 1982 Tommeras et al., 1984). 

That microorganisms in the gut of an insect are capable of converting substances from food plants into chemicals which can be used as pheromones has been demonstrated by several authors. Thus while Pearce et al. 171) reported that a// Aa-cubebene (11) one of the components in the aggregation pheromone released by Scolytus multistriatus, is produced by the host. Brand et al 172) found that a bacterium isolated from the gut of Ips paraconfusus converts alpha-pintnQ (12) to cis- and trans-wQvhQnol (13, 14) and myrtenol (15). 

Bark beetles (Birch, Chapter 12) and many other Coleoptera (Carde and Baker, Chapter 13) are attracted to aggregation and sex pheromones, but the mechanisms these insects use to fly to these sources are poorly documented and understood. The elm bark beetle, Scolytus multistriatus, in a wind tunnel, has been shown to fly horizontally upwind over a meter in the presence of synthetic pheromone, an anemotactic response (Choudhury and Kennedy, 1980). A major feature of bark bettle host colonization and mate recruitment is mass attack this dictates that the pheromone emanates from a relatively large source such as a section of a tree beetles may also orient to the visual cues from the tree trunk. 

Choudhury, J. H. and Kennedy, J. S. (1980) Light versus pheromone-bearing wind in the control of flight direction by bark beetles, Scolytus multistriatus. Physiol. Ent., 5, 207-14. 

Isolation and identification techniques have since become more sophisticated. Extraction of frass did lead to identification of the pheromone of D. brevicomis, but other pheromones have been isolated by condensation of the air from around logs containing boring male beetles (e.g., I. pini, Browne et al., 1974 Birch et al., 1980a) (Fig. 12.2), by extraction from the hind-guts of male beetles (e.g., I. grandicollis Vit6 and Renwick, 1971), or by the absorption of pheromone-laden air on a substrate (such as Porapak ) and its later extraction by solvent (e.g., Scolytus multistriatus, Pearce et al., 1975). 

The titanium-mediated homologation of homoallylic alcohols is the last but one step in a straightforward synthesis of the (racemic) pheromone of the bark beetle Scolytus multistriatus (Scheme 1-18). The key intermediate e // ro-4-methyl-5-hexen-3-ol (23)... 

Lanier, G. N., R. M. Silverstein, and J. W. Peacock Attractant pheromone of the European elm bark beetle (Scolytus multistriatus) Isolation, identification, synthesis, and utilization studies. In J. F. Anderson and H. K. Kaya, Eds., Perspectives in Forest Entomology. New York Academic Press. 1976. 

CgH.gO, Mr 130.23, bp. 160-161 °C. The (3S,45)-iso-mer, [a]n -23.3° (hexane), an important component of the aggregation pheromone (see pheromones) of bark beetles of the genus Scolytus, e.g. the smaller European bark beetle. S. multistriatus is a carrier of the fungus Ceratocystis ulmi causing death of elm trees. It also occurs in ants. The (3/ ,45)-stereoisomer is a trail pheromone of the ant Leptogenys diminuta, see also multistriatin. 

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