2-Methyl-6-methylene-7-octen

Chemical shift nonequivalence of the methyl groups of an isopropyl moiety near a chiral center is frequently observed the effect has been measured through as many as seven bonds between the chiral center and the methyl protons. The methyl groups in the terpene alcohol, 2-methyl-6-methylen-7-octen-4-ol (ipsenol) are not chemical shift equivalent (Figure 3.55). They are diastereotopic, so a strong magnetic field is usually necessary to avoid superposition. 

FIGURE 3.55 2-Methyl-6-methylen-7-octen-4-ol (ipsenol) in CDCT3 at 300 MHz. Titration with C6D6. The sample was a gift from PheroTech, Inc., Vancouver, BC, Canada. 

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)... 

As an example of this strategy, let s consider the synthesis of 2-methyl-6-methylene-7-octen-4-ol, an insect pheromone. (As described in the Focus On box on pages 1025-1026, pheromones are compounds used by animals, especially insects, for communication.) The synthesis of this alcohol, a component of the sex attractant of the male bark beetle, has been described in the literature. Retrosynthetic analysis, similar to that described earlier, suggested the use of a Grignard reaction to prepare this alcohol ... 

Figure 5.1a (Continued) octadiene-3,6-diol) (11) hydroxycitronellol (3,7-di methyloctane-l,7-diol) (12) 8-hydroxydihydrolinalool (2,6-dimethyl-7-octene-l,6-diol) (13) 7-hydroxygeraniol (E-3,6-dimethyl-2-octene-l,7-diol) (14) 7-hydro-xynerol (Z-3,6-dimethyl-2-octene-l, 7-diol) (15) cis and trans 8-hydroxy linalool (E- and Z-2,6-dimethyl-2,7-octadiene-l,6-diol) (16) p-menthenediol I (p-menth-l-ene-7,8-diol) (17) E-geranic acid (3,7-dimethyl-2,6-octadienoic acid) (18) E-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid (19) E- and Z-sobrerol or p-menthenediol II (p-menth-l-ene-6,8-diol) (20) cis and trans rose oxide (21) nerol oxide (22) 2-exo-hydroxy-1,8-cineol (23) 1,8-cineol (24) wine lactone (25) cis and trans 1,8-terpin (26) triol (2,6-dimethyloctane-2,3,6-triol) (27) hotrienol [(5E)-3,5-dimethylocta-l,5,7-trien-3-ol] (28) myrcenol (2-methyl-6-methylene-7-octen-2-ol)...

Lippia dauensis (Chiov.) Chiov. L. dauensis oil was obtained from plants collected in the north-eastern arid region of the country. The semi-dried leaves and flowering tops of the plant produced 2.4% oil contaiiung p-ocimene (24.7%), 2-methyl-6-methylene-7-octen-4-one (15.7%), myrcene (12.9%), cis-tagetone (11.0%), and 2-methyl-6-methylene-2,7-octadien-4-ol (9.4%). The... 

Methyl-6-methylene-7-octen-2-ol acetate. See Myrcenyl acetate... 

CAS 1118-39-4 EINECS/ELINCS 214-262-0 Synonyms 2-Methyl-6-methylene-7-octen-2-ol acetate 7-Octen-2-ol, 2-methyl-6-methylene, acetate... 

Compound EADl subjected to GC>secondary column, matched well with 1k(eadi) = 1108 corifirining the same identity in both GC-EAD and GCxGC-TOFMS analysis. Spectrum, retention and GC-EAD behaviour of compound EADl was identical to that obtained for synthetic ipsenol (2-methyl-6-methylene-7-octen-4-ol, 1). 

Metabolic pathways of myrcene (302) and citronellene (309) by microorganisms and insects are summarized in Figure 19.205. (3-Myrcene (302) was metabolized with D. gossypina ATCC 10936 (Abragam et ah, 1985) to the diol (303) and a side product (304). p Myrcene (302) was metabolized with G. applanatum, P. flabellatus, and P. sajor-caju to myrcenol (30 (2 methyl-6-methylene-7-octen-2-ol) and 306 (Busmann and Berger, 1994). 

The direct reaction of 2-trimethylsilylmethyl-1,3-butadiene with isovaleraldehyde gives ( )-ipsenol (2-methyl-6-methylene-7-octen-4-ol) in rather low yield (30%) (eq 5). However, ipsenol is obtained in 62% overall yield by the reaction of 2-trimethylsilylmethyl-1,3-butadiene with isovaleryl chloride, followed by reduction with diisobutylaluminum hydride (eq 7). Similarly, ( )-ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol) is obtained by reduction of myrcenone, prepared by the reaction of 2-trimethylsilylmethyl-1,3-butadiene with 3,3-dimethylacryloyl chloride, in 75% overall yield (eq 8). 

Mori, K. Synthesis and absolute configuration of (-)-ipsenol (2-methyl-6-methylene-7-octen-4-ol), the pheromone of Ips paraconfusus Lanier. Tetrahedron Lett. 1975,... 

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