Trypodendron lineatum

The synthesis of lineatin, a pheromone of the insect Trypodendron lineatum, involves the enantioselective addition of methane to the double bond of alkene A in the presence of a chiral rhenium catalyst on silica (Re /silica see Figure 2.19). Michael performed eight separate experiments for this reaction in a 500 mL high-pressure stirred autoclave reactor using liquid methane as a solvent and 0.05 mmol catalyst. The results are shown in Table 2.2. 

Bioassay and histological data indicate that sex pheromone is produced in the hindgut of Trypodendron lineatum (Schneider and Rudinsky, 1969). Epithelial cells of the hindgut of attractive females are larger and taller, richer in vacuoles, and also possess larger granular nuclei, compared with structures in non-attractive females. The epithelial cells rest on the cuticle, which protrudes into the base of the cells. 

Schneider I. and Rudinsky J. A. (1969) The site of pheromone production in Trypodendron lineatum (Coleoptera Scolytidae) bioassay and histological studies of the hindgut. Can. Entomol. 101, 1181-1186. 

Borden J. H. and Slater C. E. (1969) Sex pheromone of Trypodendron lineatum production in the female hindgut-Malpighian tubule region. Ann. Ent. Soc. Am. 62, 454-455. 

Borden J. H., Oehlschlager A. C., Chong L., Slessor K. N. and Pierce H. D., Jr, (1980a) Field tests of isomers of lineatin, the aggregation pheromone of Trypodendron lineatum (Coleoptera Scolytidae). Can. Entomol. 112, 107-109. 

Hoover S. E. R., Lindgren B. S., Keeling C. I. and Slessor K. N. (2000) Enantiomer preference of Trypodendron lineatum and the effect of pheromone dose and trap length on response to lineatin-baited traps in interior British Columbia../. Chem. Ecol. 26, 667-677. 

MacConnell J. G., Borden J. H., Silverstein R.M. and Stokkink E. (1977) Isolation and tentative identification of lineatin, a pheromone from the frass of Trypodendron lineatum (Coleoptera Scolytidae). J. Chem. Ecol. 3, 549-561. 

The enantiomeric composition of lineatin in Trypodendron lineatum was not determined, but the synthesized (racemic) material was highly active in field tests (13,14). Mori et al. (Scheme 4) (13) and Slessor et al. (Scheme 5) (16) synthesized the lineatin enantiomers and reported similar optical purities, but because different solvents were used, the optical rotations cannot be compared. Since the (+) enantiomer was active in field tests (16), we may assume that it is the naturally occurring enantiomer however the presence of the antipode cannot be ruled out. 

Kandil, A.A., and Slessor, K.N., A chiral synthesis of (+)-lincatin, the aggregation pheromone of Trypodendron lineatum (olivier), from D-ribonolactone, J. Org. Chem., 50, 5649, 1985. 

Most of the new synthetic work on cyclobutane monoterpenoids concerns the insect pheromone (+ )-grandisol (295) (Vol. 2, p. 58 Vol. 4, p. 488) and (+ )-lineatin (296), a pheromone of the Douglas fir beetle, Trypodendron lineatum (Vol. 4, p. 489, Ref. 255). There are, however, two other syntheses described, and these will be dealt with first. 

Cyclobutane.—A tricyclic acetal named lineatin has been isolated from the frass of the Douglas fir beetle Trypodendron lineatum structural elucidation and synthesis have not distinguished between (104) and (105). ... 

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). 

Primary attraction has been demonstrated in several species. The clearest example is that of the ambrosia beetle Trypodendron lineatum which is attracted to ethanol produced under anaerobic conditions in dying trees (Moeck, 1970). Using host material cut or damaged to expose phloem and xylem tissues, primary attraction has also been demonstrated in four other ambrosia beetles, two Scolytus, two Dendroctonus, Ips typographus and five other species (Moeck, 1981). 

Isol. from Norway spruce infected with the ambrosia beetle Trypodendron lineatum. Host-specific pheromone. Liq. [a] " —31.9° (c, 0.5 in pentane). 

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