2.6- Nonadienal

See stmcture (107). This 4,5-position is saturated. 5-Isopropyl-8-methyl-6,8-nonadien-2-one. 5-Isopropyl-3-nonene-2,8-dione. 

Violet Leaf. Violet leaf absolute is produced by the usual extraction methods from Viola odorata (var. Victoria). It is grown mainly ia the south of France and Egypt. Although this material is not produced ia large amounts, it is quite valuable ia perfumery for its powerhil green leafy and doral character, an odor that belongs to many doral bouquets. The principal odorant ia violet leaf absolute is 2-/n j -6-i7j -nonadienal [55748-2]. 

Although the addition of hydrazine and its derivatives to acetylenic ketones has been studied in considerable detail, their interaction with hydrazones and mono-alkylhydrazones is less well known. Yandovskii and Klindukhova (74ZOR730) have studied the reaction between hydrazones and alkylhydrazones of aliphatic ketones with dipropynylketones and showed that hydrazones of acetone, methyl-ethylketone, and cyclohexane easily add to one of the triple bonds of dipropynylketone to form 4-methyl-1,1,3-trialkyl-2,3-diaza-l,4-nonadien-7-yn-6-ones (yields... 

In their synthesis of (+)-cerulenin, Mani and Townsend employed lithiated epoxysilane 157, which they trapped with (4E,7 )-nonadienal to give a 77% yield of 158, which was further manipulated to give the natural product (Scheme 5.37) [58], as-ot, 3-Epoxy-Y,S-vinylsilanes 159 are regioselectively lithiated at the a-silyl position, and can subsequently be stereo selectively trapped with a range of electrophiles to give a-substituted epoxyvinylsilanes 160, which can in turn be isomerized to a-silyl-P-vinylketones 161 (Scheme 5.38) [59]. 

Dioxo-6-methyl-2-(2-carboxy-athyl)- 722 Bicyclo[4.3.0]nonadien-(3,7)... 

In a related coupling reaction, the reaction of diethyl 2,7-nonadien-l,9-dioate and Mg/MeOH generated a five-membered ring via coupling of an intermediate radical.Treatment of conjugated ketones with Smij in HMPA gave the coupled diketone via Wurtz-type coupling. 

Model systems indicate that aldehydes may also be produced by the action of polyphenoloxidases on amino acids in the presence of catechin, all of which are present in coffee beans at some stage between green and roasted. For example, valine yields isobutanal, leucine yields isopentanal, and isoleucine yields 2-methyl-butanal.14 Some of these aldehydes probably undergo condensation reactions in the acidic medium of the roasted bean when moisture is present.15 Some dienals in green coffee beans have recently been identified as (E,E)-2,4- and (E,Z)-2,4-nonadienal and (E,E)-2,4- and (E,Z)-2,4-decadienal.18... 

Hence, irradiation of l,l-diphenyl-8-methyl-l,7-nonadiene (5-la) in the presence of DCNB and Phen through an aqueous CuS04 filter solution (k > 334 nm) afforded octahydro-phenylanthracene 5-2a in 45% yield as the sole isomer (Scheme 5.1). In a similar way, 5-lb and 5-3 led to 5-2b and 5-4 in 57% and 71 % yields, respectively. 

Another elegant use of nonadienoate is the synthesis of a pheromone called brevicomin (148) (132). The ester was converted to 1,6-nonadiene (149). The terminal double bond was selectively converted to glycol via epoxide. The oxidation with PdCI2 produced brevicomin directly by intramolecular oxidative acetal formation. 

Diisobutylaluminium hydride catalyses the ring-closure of various dienes. It is proposed that the process involves addition of the aluminium hydride to a terminal double bond, followed by ring-closure and, finally, elimination of the catalyst (equation 106). Thus 1,5-hexadiene gives methylenecyclopentane (213) (equation 107), 1,6-heptadiene gives methylenecyclohexane (214) (equation 108), 4-vinylcyclohexene gives bicyclo[3.2.1]oct-2-ene (215) (equation 109) and the spiro compound 217 is obtained from 5-methylene-l,8-nonadiene (216) (equation 110)112. 

Reactions of methoxycarbonylformonitrile, furonitrile and substituted benzoni-trile oxides (4-Me, 4-OMe, 3-OMe, 4-C1, 3-C1, 2,4-di-Cl, 4-F as substituents) with dimethyl 7-(diphenylmethylene)bicyclo[2.2. l]hept-2-ene-5,6-dicarboxylate led exclusively to exo cycloadducts 82 (R = C02Me, 2-furyl, substituted phenyl), which, on irradiation with a low-pressure mercury lamp, afforded 3-azabicyclo [4.3.0]nonadiene-7,8-dicarboxylates 83 as the only products. The 1,3-dipolar cycloaddition, followed by a photorearrangement, provides a new method for obtaining tetrahydro-27/ -pyridine derivatives from cyclopentadiene (245). 

Based on a similar approach, Backvall403 established the stereochemical course of such reactions and developed efficient routes to bicyclo[4.3.0]-nonadiene and bicyclo[5.3.0]-decadiene systems. Backvall404 has also reported a Pd(02CCF3)2-catalyzed oxidative carbocyclization of allenenes (Scheme 125). The process is efficient even with catalyst loading as low as 1 mol%, although if requires/>-benzoquinone as the stoichiometric oxidant, which represents the first example of a C-C bond formation using a catalytic amount of Pd(ll). Bicyclic adducts have been obtained in... 

The metal-mediated and metal-catalyzed [6 + 2]- and [6 + 4]-cycloaddition reactions, pioneered by Pettit and co-workers105 106 and Kreiter and co-workers,107 respectively, involve the cycloaddition of metal-complexed cyclic trienes with 7r-systems such as alkenes, alkynes, and dienes. The [6 + 2]-reactions produce bicyclo[4.2.1]nonadiene derivatives and the [6 + 4]-reactions produce bicyclo[4.4.1]undecatrienes (Scheme 32). Trienes complexed to chromium, which can be prepared on large scale (40 g) as reported by Rigby and co-workers,108 react with 7r-systems upon thermolysis or irradiation.109-111 Chromium and iron-catalyzed [6 + 2]-reactions of cycloheptatrienes and disubstituted alkynes... 

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