Nonatrienal

The novel highly substituted spiro[4.4]nonatrienes 98 and 99 are produced by a [3+2+2+2] cocyclization with participation of three alkyne molecules and the (2 -dimethylamino-2 -trimethylsilyl)ethenylcarbene complex 96 (Scheme 20). This transformation is the first one ever observed involving threefold insertion of an alkyne and was first reported in 1999 by de Meijere et al. [81]. The structure of the product was eventually determined by X-ray crystal structure analysis of the quaternary ammonium iodide prepared from the regioisomer 98 (Ar=Ph) with methyl iodide. Interestingly, these formal [3+2+2+2] cycloaddition products are formed only from terminal arylacetylenes. In a control experiment with the complex 96 13C-labeled at the carbene carbon, the 13C label was found only at the spiro carbon atom of the products 98 and 99 [42]. 

Scheme 20 Formation of highly substituted spiro [4.4]nonatrienes 98 and 99 from the (T-dimethylamino-2 -trimethylsilyl)ethenylcarbene complex 96 and arylacetylenes 97 [42,81]...

Hydroxy-9-methoxy-3,7-dimethyl-1 - [2,6,6-trimethyl-cyclohexen-( 1 )-yl ]-nonatrien-(I,4,6)... 

The ozonolysis of carotenoids was employed in order to obtain oxygenated cleavage products for biological tests, for example, for lycopene. In this case, among a series of products, one product formed by a double oxidative cleavage was purified and characterized as ( , ,/ )- 4 - methyl - 8 -oxo-2,4,6-nonatrienal, and it was shown to be active in the induction of apoptosis in HL-60 cells (Zhang et al. 2003). 

The bicyclo[6.1.0]nonatriene 46 is transformed to the 8,8-dihydroindene on treatment with a catalytic amount of [Rh(CO)2Cl]2 [24], The stereoselectivity depends on the reaction temperature. [5 + 2]cycloaddition of vinylcyclo-propanes 47 with alkynes is catalyzed by RhCl(PPh3)3 in the presence of silver triflate to give seven-membered rings 48 [25]. (Scheme 17 and 18)... 

A particularly instructive example is the thermolysis of (Z)-l,3,8-nonatriene in which an intramolecular Diels-Alder reaction competes with a sigmatropic [1,5] hydrogen shift (Scheme 24). The use of high pressure here enables a reversal of the selectivity. At 150°C and 1 bar the [1,5] hydrogen shift passing through a monocyclic transition state is preferred. At 7.7 kbar the intramolecular Diels-Alder reaction is preferred due to its bicyclic transition state. 

SCHEME 24. The effect of pressure on the competitive rearrangements of cw-l,3,8-nonatriene... 

In summary, the parent 1,3-bishomotropylium ion [43] is produced upon protonation of the bicyclo[6.1.0]nonatriene [44] and its NMR spectrum was recorded under stable ion conditions. Two different bridged 1,4-bishomo-tropylium ion skeletons [45] and [46] have been prepared from a multitude of different precursors. However, no unbridged 1,4-system has yet been characterized. 

Roth also studied the one-electron oxidation product [157b] of 9-methylenebicyclo[4.2.1]nonatriene [157a], It was assumed that the initial oxidation was to [157c] followed by a rapid intramolecular cycloaddition to [157b], The barrier to this addition was estimated at about 5 kcal mol-1. 

A diazide was obtained91 as the sole product also by addition of IN3 in acetonitrile to c -bicyclo[6.1.0]nonatriene. In this case, however, at variance with the medium-size ring unsaturated compounds, the reaction did not afford a normal vie-diazide. A mechanism involving a bishomotropylium or cyclopentadienyl cation has been proposed (equation 64). 

Only few examples have been reported so far on nucleophilic addition reactions to acceptor-substituted polyenes123,124,186 188. In 1933, Farmer and Martin186 examined the reaction of methyl 2,4,6-octatrienoate with sodium dimethyl malonate and isolated the 1,4-adduct as major product (equation 81). In contrast to this, 3,5,7-nonatrien-2-one and ethyl 2,4,6-octatrienoate react with organocuprates under 1,8-addition to provide the 4,6-dien-2-ones and 3,5-dienoates, respectively (equation 82)187. 

Attractive Compounds. The male-produced pheromones of sap beetles, known so far, show the rather stereotypic structures 125-147 (Scheme 15) methyl- and ethyl-branched hydrocarbons with three or four (T)-configured conjugated double bonds [4]. Up to now, 23 compounds could be identified, forming species specific mixtures. Major components in the bouquets are (2E,4E,6E)-5-ethyl-3-methyl-2,4,6-nonatriene, 128, in Carpophilus davidsoni [268] as well as in C.freemani [269], (2 ,4 ,6 )-4,6-dimethyl-2,4,6-nonatriene, 129,in C. truncatus [270], (3 ,5 ,7 )-5-ethyl-methyl-3,5,7-undecatetraene, 132, in C. mutillatus [271],(2 ,4 ,6 ,8 )-3,5,7-trimethyl-2,4,6,8-decatetraene, 134,in C. hemipterus [272] as well as C. brachypterus [273], (2 ,4 ,6 ,8 )-3,5,7-tri-... 

Fig. 11.1 Simplified scheme of the emission and function of herbivore-induced plant volatiles in plant defense. DMNT, 4,8-dimethyl-l,3,7-nonatriene) TMTT, 4,8,12-trimethyltrideca-l,3,7, 11-tetraene...

Degenhardt J, Gershenzon J (2000) Demonstration and characterization of ( )-nerolidol synthase from maize a herbivore-inducible terpene synthase participating in (3- )-4, 8-dimethyl-1,3,7-nonatriene biosynthesis. Planta 210 815-822... 

The male-produced volatiles eficiting responses from male and female antennae of the sap beetle, Colopterus truncatus Randall (Coleoptera Nitidulidae), were identified as (2A ,4A ,6A )-3,5-dimethyl-2,4,6-octa-triene, 2E, AE, 6T )-4,6-dimethyl-2,4,6-nonatriene and 2E, AE,6E,SE) 3,5,7-trimethyl-2,4,6,8-decatetraene. A fourth male-specific compound... 

Two male-produced aggregation pheromone compounds from the eggplant flea beetle Epitrix fuscula, were identified by synthesis as 2E, AE, 6Z)-2,4,6-nontrienal and 2E, AE, 6E)-2,A,6-nonatrienal. ... 

Nine compounds from branches with leaves and green fruit from apple consistently elicited an antennal response in codling female moths (Cydia po-monella, Lepidoptera), including methyl salicylate, ( )-/3-farnesene, /3-caryo-phyllene, 4,8-dimethyl-f,3( )-7-nonatriene, (3Z)-hexenol, (Z, )-a-farnesene, ( , )-a-farnesene, linalool and germacrene D [378]. 

Fig. 2.4. Chromatographic profiles of volatiles emitted by four plant species at different time periods after an attack by Spodoptem littoralis larvae. The labeled peaks are 1, (Z)-3-hexenal 2, ( )-2-hexenal 3, (Z)-3-hexenol 4, (Z)-3-hexenyl acetate 5, linalool 6, ( )-4,8-dimethyl-1,3,7-nonatriene 7, indole 8, ( )-/ -caryophyllene 9, ( ,)-o -bergamotene 10, ( >/3-farnesene 11, ( , )-of-farnesene 12, nerolidol 13, ( , )-4,8,12-trimethyl-1,3,7,11-tridecatetraene 14, of-pinene 15, /3-pinene 16, -myrcene 17, D-limonene 18, ( )-/3-ocimene 19, -sesquiphellandrene 20, germacrene D. Two internal standards, -octane and nonyl acetate, are labeled with IS1 and IS2, respectively.

Fig. 5.1. A sample of floral scent compounds. (1) Substituted methyl esters of benzoic acid. The ester smells unpleasantly sweet when R = H (methyl benzoate), of wintergreen when R = OH (methyl salicylate), and of concord grape when R = NH2 (methyl anthranylate). Odorants with unusual origins and biological functions include the homoterpene 4,8-dimethyl-1,3,7-nonatriene (2) and the wet-earth compound geosmin (3). Some ubiquitous fragrance compounds are ben-zaldehyde (4), benzyl alcohol (5), indole (6), (S)-linalool (7), ( )-/ -ocimene (8), and of-farnesene (9).

The Wittig methylenation of geranial to (E)-4,8-dimethyl-l,3,7-nonatriene is best carried out with phenyl 1ithium 1n tetrahydrofuran as described in Part... 

Conjugated linear trienes were reported to undergo cyclization to form seven-membered ring systems.112 Cyclic polyenes, in turn, isomerize to yield bicyclic compounds. In the transformation of nonatriene (10), the role of the base was demonstrated to catalyze the formation of the conjugated triene [Eq. (4.23)], which... 

All of-cyclononatriene (53) cyclizes in the predicted disrotatory manner at measurable rates at 25-50°C to the bicyclic diene 54.115 The nine-membered ring is large enough to accommodate a trans double bond trans-cis-cis-cyclo-nonatriene (55), obtained by conrotatory photochemical opening of 54, cyclizes to the trans fused bicyclononadiene 55.116... 

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