Carbonylation 1-decene

Other reactions shown to occur at the same rate under the two heating methods include the acid-catalyzed isomerization of carvone 40 to carvacrol 41 [33], and ene reactions involving carbonyl enophiles (Scheme 4.21) [32], The former reaction was performed in a mixture of chlorobenzene (slightly polar) and dioxane (nonpolar) and in the latter reaction a large excess of 1-decene was used and so the reaction was effectively performed in a solution of low polarity. 

The alkene 1-decene (24) was poorly reactive in the carbonyl-ene reaction with ethyl mesoxalate and required a temperature up to 170 °C for a very long time (5 h) [42]. When performed in a homogeneous liquid medium at the same temperature but under the action of MW irradiation the reaction gave a similar result. Reaction time was appreciably shortened by use of GS/MW coupling [30]. Thus, irradiation at 60 W for only 10 min led to the ene adduct 25 in 50% yield (Scheme 7.2). Under these conditions a maximum temperature of 230 °C was measured. To obtain the same yield with conventional heating at 170 °C reaction for 1 h is required. The stereoselectivity of the reaction was not related to the mode of heating. A higher con-... 

Grosjean, E., Grosjean, D., and Seinfeld, J.H. Atmospheric chemistry of 1-octene, 1-decene, and cyclohexane gas-phase carbonyl and peroxyacyl nitrate products. Environ. ScL Technol, 30(3) 1038-1047, 1996. 

The allylic alcohol substitution reaction may also be carried out in DMF solution with sodium bicarbonate as the base at 100 to 125° with palladium-phosphine catalysts, in which case only carbonyl products are formed. With this catalyst combination nonallylic, unsaturated alcohols also react to form carbonyl compounds in good yields. For example, in an extreme case, 9-decen-l-ol and bromobenzene gave some 10-phenyldecanal (40) ... 

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]. 

Some of the carbonyl compounds and alcohols form important aroma components in various foods. l-Octene-3-one and l-octene-3-ol are the main components of fresh mushroom aromas. From the series of aldehydes, 2-heptenal to 2-decenal are found in potato chips, and 2-nonenal forms an important component of the aroma in carrots. 

Steric factors in the olefin substrate can severely retard carbonylation with the platinum catalysts. For example olefins such as 2-decene, cyclohexene or 2,4,4-trimethyl-1-pentene are unreactive. 

The carbonyl profile of freshly ground C. arietinum grain was studied later and 18 different compounds were identified [91] of which ten were new to those identified in the study by Rembold [89]. They confirmed the presence of 98, 99, 100, 105, 107, 108, 109, 110 but also identified formaldehyde (213), acetaldehyde (214), butanal (215), pentanal (216), octanal (217), octanone (218), octenal (219), nonenal (220), decenal (221) and decadienal (222) [91]. They noted that the concentration of total... 

Polypyrrole, a conducting polymer, is an effective redox system for a palladium catalyst for the oxidation of olefinic compounds with oxygen in acetonitrile/water to the respective carbonyl compounds [91]. 1-Decene and terminal olefins with oxygen functions have been used in these experiments. 

Fig. 2-1 Carbonylation ofl-decene in a high-pressure iR apparatus catalyst [(PPhslsCuClj/tetramethylethylenediamine, solvent THF.

Titanium. Catalyses of hydrogenation of alkenes, alkynes, carbonyl-, and nitro-compounds have been described. The effect of the nature of the ligand L and of the alkene to be reduced on reactivity in catalytic hydrogenation by Ti(7r-C5H5)2L2 has been quantitatively studied. The dependence of rate constants on solvent for reduction of decene in the presence of Ti(7r-C5H5)Me+ is interpreted in terms of electrostatic interaction between the active ionic species and the solvent. There is also a thermochemical report relevant here, and that is of a determination of the heats of mixing of cyclohexene and of hex-l-ene with titanium tetrachloride. The heats of mixing are close to zero, which implies very small heats of complex formation between these alkenes and titanium. ... 

The use of secondary alcohols as reductants for DODH was first reported by Elhnan, Bergman, and coworkers, who employed Re-carbonyl compounds, e.g., Re2(CO)io, as pre-catalysts under aerobic conditions (Scheme 16) [36]. Optimized conditions used the glycol substrate with the mono-alcohol as the solvent, e.g., 3-octanol, at 150-175°C, with 1-2.5 mol% Re2(CO)io and TsOH as a co-catalyst (2-5 mol%). Good yields of the olefin (50-84%) were obtained with representative glycols. The sy -3,4-decanediol was converted highly selectively to trans-3-decene, implicating a sy -eUmination process in the diol to olefin conversion (Scheme 17). Erythritol was converted moderately efficiently to 2,5-dihydrofuran (62% yield), presumably the result of initial 1,4-diol dehydration followed by DODH of the THF-diol intermediate. The nature of the active catalyst was unknown at the time, but was speculated to be an oxidized Re species. 

Phospholipids contribute specific aroma to heated milk, meat and other cooked foods through lipid oxidation derived volatile compounds and interaction with Maillard reaction products. Most of the aroma significant volatiles from soybean lecithin are derived from lipid decomposition and Maillard reaction products including short-chain fatty acids, 2-heptanone, hexanal, and short-chain branched aldehydes formed by Strecker degradation (reactions of a-dicarbonyl compounds with amino acids). The most odor-active volatiles identified from aqueous dispersions of phosphatidylcholine and phos-phatidylethanolamine include fra 5 -4,5-epoxy-c/5-2-decenal, fran5,fran5-2,4-decadienal, hexanal, fra 5, d5, d5 -2,4,7-tridecatrienal (Table 11.9). Upon heating, these phospholipids produced cis- and franj-2-decenal and fra 5-2-undecenal. Besides fatty acid composition, other unknown factors apparently affect the formation of carbonyl compounds from heated phospholipids. 

A large number of volatile compounds have been identified in beef fat (Table 11.17). The flavor significance of individual volatile compounds can be calculated on the basis of their threshold values. Thus, two of the carbonyl compounds formed in the smallest concentrations, c/5-4-heptenal and rran, tran5 -2,6-nonadienal, were the most flavor significant. More sensitive GC-MS analyses reported odor threshold values of 1260 ppb for cw-4-heptenal and 1231 for tra 5, d5 -2,6-nonadienal found among fish oil volatiles (Section E.3 and Chapter 5). On the other hand, the most abundant carbonyl, 2-decenal, was the least flavor significant. 

A corr5)arison of the sensory properties (Table 3.32) shows that some carbonyl compounds, belonging to side components of the volatile fractions, may intensively contribute to an off-flavor due to their low threshold values. Food items containing linoleic acid, especially (E)-2-nonenal, trans-4,5-epoxy-(E)-2-decenal and l-octen-3-one, are very aroma active. 

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). ... 

---