8-Decen-2-lactone

Aeollanfhus suaveoiens Mart, ex Spreng Lamiaceae Bra leaves convulsions +PTZ +EST -FTZ -EST + EST + PTZ essential oil linalool (2) S-decanolactone 5-decen-2-lactone 5-decano aclone S-decen-2- actone f-decanolactone 43 44... 

IOf)-Hydroxy-7-oxo-2f3-carboxy-trans-bicyclo [4.4.0]decen-(3)-lacton y... 

Additional representatives of six-membered 5-lactones are 5-decalactone 155, constituent of fruits, cheese and dairy products with creamy-coco nut and peachy aroma, jasmolactone 156 as well as 5-2-decenolactone (2-decen-5-olide) 157 (Structure 4.47). 

The closely related 5-decanolide (5-decalactone), not only found in many fruits but also found in dairy products, exhibits a creamy-coconut, peach-like aroma [49] and can be synthesised from the corresponding a,(3-unsaturated lactone 2-decen-5-olide found in concentrations of up to 80% in Massoi bark oil using basidiomycetes or baker s yeast [229]. After about 16 h of fermentation, 1.2 g 5-decanolide was obtained. At the same time, the minor lactone in... 

Spiroannelation.2 Acylation of 1 by the cnol lactone 2 results in formation of only one (3) of the two possible spiro[4.5]decenes. The hulky isopropyl group is... 

One-electron oxidation systems can also generate radical species in non-chain processes. The manganese(III)-induced oxidation of C-H bonds of enolizable carbonyl compounds [74], which leads to the generation of electrophilic radicals, has found some applications in multicomponent reactions involving carbon monoxide. In the first transformation given in Scheme 6.49, a one-electron oxidation of ethyl acetoacetate by manganese triacetate, yields a radical, which then consecutively adds to 1-decene and CO to form an acyl radical [75]. The subsequent one-electron oxidation of an acyl radical to an acyl cation leads to a carboxylic acid. The formation of a y-lactone is due to the further oxidation of a carboxylic acid having an active C-H bond. As shown in the second equation, alkynes can also be used as substrates for similar three-component reactions, in which further oxidation is not observed [76]. 

The aldehydes are generated at temperatures as low as 60 C. O-f particular note is the oxidation o-f phospholipids and polyunsaturated -fatty acids. It is the oxidative products o-f arachidonic acid -from the phospholipid -fraction in chicken, yielding cis—4-decenal, trans-2-cis—5—undecadienal, and trans-2-cis—4— trans-7—tridecatrienal that are responsible -for the species identity o-f chicken. At temperatures o-f 200 to 300 C the thermal oxidative reactions allow the -formation o-f ketones and lactones as well as aldehydes. 

Adam, W., Kliem, U., Peters, E. M., Peters, K., Von Schnering, H. G. Preparative vis-laser photochemistry. Qinghaosu-type 1,2,4-trioxanes by molecular oxygen trapping of Patemo-Buchi triplet 1,4-diradicals derived from the bicyclic enol lactones D1,6- and D1,10-2-oxabicyclo[4.4.0]decen-2-one and p-benzoquinone. J. Prakt. Chem. 1988, 330, 391-405. 

These terpene notes are supported by (Z)-3-hexenol, (E)-2-hexenal, (E)-2-hexenol with their fresh, green character. Gamma- and delta-lactones (4-decanolide, 5-decan-olide, 4-dodecanolide, 5-dodecanolide-(Z)-7-decen-5-olide) impart the sweet, creamy, buttery, peach and apricot character. 2,5-Dimethyl-4-hydroxy-furan-3(2H)-one and 2,5-dimethyl-4-methoxy-furan-3(2H)-one are responsible for the sweet creamy fruity body. A bouquet of esters imparts the overall fruity character (mainly esters of ethyl-, (Z)-3-hexenyl and butyl alcohol with acetic-, butanoic-, 2-butenoic, 3-hydroxybutanoic- and hexanoic acid). 

Jasminfe) lactone [(Z)-7-decen-5-olide, jasmolac-tone]. 

Camphanic acid, T"4.2 2-Ethyl-5-hydroxy-4,5-dimethylhex-2-ene-l,6-dioic acid lactone, K"8.9 Intergerrinedc acid lactone, K"8.12 8-Hydroxy-4-oxo-6-decen-9-olide, Y"11.2... 

Methyl-6-isoprenyl-9-decen-l-ol acetate, T"11.4 5-Hydroxyhexadecanoic acid lactone, A"9.5... 

The corresponding homogeneous complexes (104-108) were tested in various processes, including (i) ROMP of COE (ii) CM of 5-decene with 5-hexenyl acetate to produce the insect pheromone 5-decenyl acetate [92] and (iii) the macrocychc RCM of 5-hexen-l-yl-lO-undecenoate to generate the 16-membered ring lactone [86]. The pyridine-alkoxide-modified catalysts were foimd to react more slowly than the commercial catalysts for the ROMP of COE, but displayed good activities for the CM and macrocychc RCM reactions. 

In addition to the 5-lactones of structure (41), other lactonic aroma components with a saturated ring are known, the structure of which, however, is somewhat different from that of the n-series represented by (41). These are 6-hydroxy-5-hexanolide (42), identified in tomato (557), and three cyclic compounds carrying an unsaturated chain in position 5, viz. (Z)-7-decen-5-olide (jasmine lactone) (44) 712), identified in the flavor of black tea (50) together with methyl jasmonate (779). (Z)-9-dodecen-5-olide (45) and (Z)-9-tetradecen-5-olide (46), the latter two lactones having been isolated from butter flavor (50, 725). On the other hand, lactone (43) was isolated from milk where it is present in a quantity of 10 pg/kg (0.001 ppb) (247) this quantity, however, is probably much lower than the threshold value. 

Chang et al. [73] and Nawar et al. [74] have identified many of the volatiles formed during deep fat frying. They have found numerous acids, alcohols, aldehydes, hydrocarbons, ketones, lactones, esters, aromatics, and a few miscellaneous compounds (e.g., pentylfuran and 1,4-dioxane) as products of deep fat frying. More recently, Wagner and Grosch [75] have studied the key contributors to French fry aroma. The list of key aroma compounds in French fries includes 2-ethyl-3,5-dimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, 3-isobutyl-2-methoxypyrazine, (E,Z), (E,E)-2,4-decadienal, trans-4,5-epoxy-(E)-2-decenal, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, methylpropanal, 2- and 3-methylbutanal, and methanethiol. If one examines this list, it is obvious that the Maillard reaction (pyrazines, branched chain aldeydes, furanones, and methional), and lipid oxidation (nnsaturated aldehydes) are the primary sources of this characteristic aroma. 

It is interesting that the 8-decalactone is formed by an entirely different biotrans-fonnation. This lactone is formed by the miCTobial reduction of an a,P-unsaturated lactone found in Massoia bark oil. Massoia bark oil contains about 80% 2-decen-5-ohde, 1% 2-dodecen-5-olide and 6% benzyl benzoate. Several microorganisms... 

In the AEDA of UHT milk (Table 10.38), 5-decalactone, which contributes to the aroma of butter (Table 10.40) as well as unripened and ripened cheese (cf. 10.3.5), is the predominant aroma substance. Apart from other lactones, 2-acetyl-l-pyrroline, methional, 2-acetyl-2-thio-azoline and 4,5-epoxy-2-decenal are among the identified aroma substances. 

Hydroxyhexanoic acid ethylester (E,E)-2,4-Decadienal trans-4,5-Epoxy-(E)-2-decenal Wine lactone Vanillin... 

Mono-a-arylation of carbonyl compounds with aryl halides in dioxane has been effected using the [Pd(cinnamyl)Cl]2/DalPhos catalyst system. 1-Methylimidazole exhibits unusually high efficiency as a base catalyst for conversion of ArCOCH3 to tra 5 -ArCOCH=CHNMe2 on reaction with DMF-DMA this has been ascribed to supramolecular domino catalysis. An unusual a-carboxylative y-lactonization of (g) y-alkynyl ketones (50) on reaction with CO2 has been catalysed by AgOBz with a triazabicyclo decene (Scheme 38). ... 

Reiser and coworkers reported the enantioselective synthesis of five paraconic acids with interesting antibiotic and antitumor properties [23]. These 3-carboxylic acid-substituted y-butyrolactones differ inter alia by their side chain at C4, which were attached by CM (Scheme 10.14). For the synthesis of roccellaric acid, lactone 47a was treated with 1.5 equiv. of 1-dodecene and catalyst [Ru]-I. Compound 48a was obtained in 57% yield as a 3.5 1 mixture of E- and Z-isomers. In an analogous way, CM of lactone 47b with 1-decene furnished 48b, a precursor ofnephrosteranic acid, in 53% yield. Even though a large excess of 1-decene (4 equiv.) and the more active catalyst [Ru]-II were used, the conversion was not complete (27% recovered 47b). However, the selectivity was much higher in the latter case (EfZ = 7 1). 

---