Ketone Unsaturated, from aldehyde

By catalytic reduction of a p-unsaturated ketones, prepared from aldehydes by the Claisen - Schmidt reaction (see under Aromatic Aldehydes), for example ... 

Hydroxyalkyl Alkyl Peroxides and Hydroxyalkyl Peroxyesters. The same stmctural restrictions discussed for the hydroxyhydroperoxides apply for the hydroxyalkyl alkyl peroxides, and those that exist are derived from aldehydes and certain ketones having electron-withdrawing groups, eg, polyfluorinated a,P-unsaturated ketones (136). 

Vinyllithium [917-57-7] can be formed direcdy from vinyl chloride by means of a lithium [7439-93-2] dispersion containing 2 wt % sodium [7440-23-5] at 0—10°C. This compound is a reactive intermediate for the formation of vinyl alcohols from aldehydes, vinyl ketones from organic acids, vinyl sulfides from disulfides, and monosubstituted alkenes from organic halides. It can also be converted to vinylcopper [37616-22-1] or divinylcopper lithium [22903-99-7], which can then be used to introduce a vinyl group stereoselectively into a variety of a, P-unsaturated systems (26), or simply add a vinyl group to other a, P-unsaturated compounds to give y, 5-unsaturated compounds. Vinyllithium reagents can also be converted to secondary alcohols with trialkylb o r ane s. 

Similarly, methyl vinyl ketone has been added to enamines derived from aldehydes (3,321,324-327) and ketones (3,328), providing a useful extension of the Robinson annelation reaetion. Condensations of enamines with other a, 3-unsaturated ketones can give a variety of diketones (329). 

The reactions of dichlorocarbene with morpholine and piperidine enamines derived from cyclopentanone and cyclohexanone have been reported to lead to ring expanded and a-chloromethylene ketone products (355,356). Similarly a-chloro-a, -unsaturated aldehydes were obtained from aldehyde derived enamines (357). Synthesis of aminocyclopropanes (353,359) could be realized by the addition of diphenyldiazomethane (360) and the methylene iodide-zinc reagent to enamines (367). 

The imines are prepared by 16-12. The enamine salt method has also been used to give good yields of mono a alkylation of a,P-unsaturated ketones. Enamines prepared from aldehydes and butylisobutylamine can be alkylated by simple primary alkyl halides in good yields. N-alkylation in this case is presumably prevented by steric hindrance. 

The Horner-Wittig reaction of a-phosphoryl sulphoxides 442, which are chemically stable, results in the formation of a, -unsaturated sulphoxides 443 in high yields (equation 264). The reaction has been found to be non-stereoselective, mixtures of E and Z isomers being formed from aldehydes and unsymmetrical ketones . In the case of aromatic aldehydes this reaction can also be advantageously performed in a two-phase catalytic system even without the usual PTC catalysts (Table 24). Intramolecular Horner-Wittig reaction of a-phosphoryl-5-oxosulphoxides 444 leads to a, -unsaturated cyclic sulphoxides 445 (equation 265). Starting from optically active 0,0-... 

Dicarbonyl derivatives from aldehydes and a,P-unsaturated ketones. The thi-azolium catalyst serves as a safe surrogate for CN. Also known as the Mi-chael-Stetter reaction. Cf. Benzoin condensation. 

According to the Cd 18-90 AOCS ° official method, the ANV is 100 times the optical density measured in a 1 cm cell, at 350 nm, of a solution containing 1.00 g of oil in 100 ml of the test solution. The measured absorbance is due to Schiff bases (167) formed when p-anisidine (166) undergoes condensation reaction with carbonyl compounds, according to equation 55. The carbonyl compounds are secondary oxidation products of lipids, such as a, S-unsaturated aldehydes and ketones derived from the hydroperoxides (see Scheme 1 in Section n.A.2.c), and their presence points to advanced oxidation of the oil. 

The chemistry of imidates and their methods of synthesis have been reviewed [32], Imidates are mainly available via the Pinner synthesis, via iminochlorides, from amides, from aldehydes and ketones, and via unsaturated systems [32]. 

R can be aryl or saturated or unsaturated alkyl. Since the cyanohydrins1476 are easily formed from aldehydes (6-49) and the product is easily hydrolyzed to a ketone, this is a method for converting an aldehyde RCHO to a ketone RCOR 1477 (for other methods, see 0-97, 0-105, and 8-9).1478 In this procedure the normal mode of reaction of a carbonyl carbon is reversed. The C atom of an aldehyde molecule is normally electrophilic and is attacked by nucleophiles (Chapter 16), but by conversion to the protected cyanohydrin this carbon atom has been induced to perform as a nucleophile.1479 The German word umpolunglm is used to describe this kind of reversal (another example is found in 0-97). Since the ion 120 serves as a... 

Although active M11O2 presents a very high selectivity for unsaturated alcohols versus saturated ones when it is employed under mild conditions, sometimes minor amounts of aldehydes or ketones resulting from the oxidation of saturated alcohols are obtained.69... 

Effect of Phospholipids on Reaction Volatiles. As would be expected, the inclusion of phospholipids in the reaction mixtures produced many volatiles derived from lipid degradation these included hydrocarbons, alkylfurans, saturated and unsaturated alcohols, aldehydes and ketones. However, two other important observations were made. First, the concentrations of most of the hetero- cyclics, formed by the amino acid + ribose Maillard reaction, were reduced. For most of the major volatiles this reduction was of the order of 40 - 50%, but in the case of thiophenethiol and methyl- furanthiol the reduction was over 65%. This appears to support the findings that in meat and coconut, lipids exert a quenching effect on the amount of heterocyclic compounds formed in Maillard reactions during heat treatment (11,12). Second, and perhaps more important, the addition of phospholipid to the reaction mixtures resulted in the production of large amounts of compounds derived from the interaction of the lipid or its degradation products with Maillard reaction intermediates. 

Homer-Wadsworth-Emmons reactions are C=C-forming condensation reactions between the Li, Na, or K salt of a /1-koto- or an a-(alkoxycarbonyl )phosphomc acid dialkyl ester and a carbonyl compound (see Figure 4.46). These reactions furnish a,/3-unsaturated ketones or 0 ,/3-unsaturated esters, respectively, as the desired products and a phosphoric acid diester anion as a water-soluble by-product. In general, starting from aldehydes, the desired compounds are produced /ra/ov-selectively or, in the case of alkenes with trisubstituted C=C double bonds, -selectively. 

C-(w-propyl)-N-phenylnitrone to N-phenylmaleimide, 46, 96 semicarbazide hydrochloride to ami-noacetone hydrochloride, 45,1 tetraphenylcyclopentadienone to diphenyl acetylene, 46, 44 Alcohols, synthesis of equatorial, 47, 19 Aldehydes, aromatic, synthesis of, 47,1 /8-chloro-og3-unsaturated, from ketones and dimethylformamide-phosphorus oxychloride, 46, 20 from alkyl halides, 47, 97 from oxidation of alcohols with dimethyl sulfoxide, dicyclohexyl carbodiimide, and pyridinium trifluoroacetate, 47, 27 Alkylation, of 2-carbomethoxycyclo-pentanone with benzyl chloride, 45, 7... 

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