Alkene and carboxylic acid

Syntheses of Aliphatic Carboxylic Acids and Derivatives. Alkenes are carbonylated in the presence of acid catalysts at 75-100°C and under pressures of 60—90 MPa (600—900 atm) to give carboxyUc acids (186). 

Avery direct synthesis of certain lactones can be achieved by heating an alkene, a carboxylic acid, and the Mn(III) salt of the acid. Suggest a mechanism by which this reaction might proceed. 

Most frequent are oxidations of alkenes that can be converted to a series of compounds such as epoxides, halohydnns and their esters, ozonides (1,2,4 tri-oxolanes), a-hydroxyketones, a-hydroxyketone fluorosulfonates, ot-diketones, and carboxylic acids and their denvatives... 

Alkenes are cleaved to carbonyl compounds by ozonolysis. This reaction is useful both for synthesis (preparation of aldehydes, ketones, or carboxylic acids) and analysis. When applied to analysis, the carbonyl compounds are isolated and identified, allowing the substituents attached to the double bond to be deduced. 

Esters of [1-(diethoxyphosphinyloxy)perfluoro-l-alkene]-phosphonic acid appear to be effective reagents for the synthesis of perfluoro-a,B-unsaturated carboxylic acids and their derivatives presumably an initially-generated perfluoroketene (166 ) is acted upon by a nucleophile (NuH=RNH2, I NH, or ROH). The ( E) / (Z) ratio of the product components increases with increasing length of R. 2 ... 

As an example we may consider the Kolbe reaction, the oxidation of carboxylic acid and carboxylates of the form R-COOH or R-COO- to form coupled hydrocarbon products of the form R2. Investigation of this reaction in aqueous and non-aqueous solvents has revealed that the processes taking place are very complex indeed. In general, the product R2 is only formed at high current densities on smooth electrodes. At lower current densities, alkenes and non-dimeric products such as R-H are found, and, especially in alkaline solutions, the product R-OH can be formed in good... 

Electrophilic substitution of the ring hydrogen atom in 1,3,4-oxadiazoles is uncommon. In contrast, several reactions of electrophiles with C-linked substituents of 1,3,4-oxadiazole have been reported. 2,5-Diaryl-l,3,4-oxadiazoles are bromi-nated and nitrated on aryl substituents. Oxidation of 2,5-ditolyl-l,3,4-oxadiazole afforded the corresponding dialdehydes or dicarboxylic acids. 2-Methyl-5-phenyl-l,3,4-oxadiazole treated with butyllithium and then with isoamyl nitrite yielded the oxime of 5-phenyl-l,3,4-oxadiazol-2-carbaldehyde. 2-Chloromethyl-5-phenyl-l,3,4-oxadiazole under the action of sulfur and methyl iodide followed by amines affords the respective thioamides. 2-Chloromethyl-5-methyl-l,3,4-oxadia-zole and triethyl phosphite gave a product, which underwent a Wittig reation with aromatic aldehydes to form alkenes. Alkyl l,3,4-oxadiazole-2-carboxylates undergo typical reactions with ammonia, amines, and hydrazines to afford amides or hydrazides. It has been shown that 5-amino-l,3,4-oxadiazole-2-carboxylic acids and their esters decarboxylate. 

Recently, the conversion of alkenes or non-activated internal alkynes into the corresponding carboxylic acids and/or butenolides has been achieved through carboxylation of titanacycle intermediates of type 73 with carbon dioxide (Scheme 27).78... 

Applications of the cross-metathesis reaction in more diverse areas of organic chemistry are beginning to appear in the literature. For example, the use of alkene metathesis in solution-phase combinatorial synthesis was recently reported by Boger and co-workers [45]. They assembled a chemical library of 600 compounds 27 (including cisttrans isomers) in which the final reaction was the metathesis of a mixture of 24 oo-alkene carboxamides 26 (prepared from six ami-nodiacetamides, with differing amide groups, each functionalised with four to-alkene carboxylic acids) (Eq.27). 

Dubois and co-workers (119,410-415) characterized alkyl (R) substituent effects in simple and sterically congested alkanes, alkenes, carboxylic acid derivatives, ketones, amines, alcohols, and so on by the use of topological parameters XR ... 

Reduction of carboxylic acids and esters, aldehydes, and nitriles, and the hydro-boration of alkenes with diborane in non-ethereal solvents is highly effective (Table 11.8), but reduction of nitro groups or cleavage of arena-halogen bonds does not occur [1]. However, in spite of the potential advantages, very little use appears to have been made of the procedure. 

CIS-[Ru(H20)2(dinso) ] is made from as-RuClj(dmso) and Ag(BF ) in aq. EtOH. The system c/s-[Ru(H20)j(dmso) ] Vaq. Na(ClO) or TBHP/CH Cl oxidised alkanes such as adamantane, cyclo-octane, -heptane and -hexane to the corresponding alcohols and ketones as did [Ru(Hj0) PWjj(0)3g ] . A free-radical mechanism may be involved for the TBHP oxidations, but those with (C10) probably involve oxoruthenate(VI) or oxoruthenate(IV) intermediates [823], The oxidative destruction of a-chlorinated alkenes by CM-[Ru(HjO)2(dmso) ] Vaq. Oxone /Me(CH3) jN(HSO ) MCj to carboxylic acids and ultimately to CO and HCl was reported [946],... 

Oxidative destruction of a-chlorinated alkenes by cA-[Ru(H30)3(dmso) ] Vaq. Oxone /Me(CH2)jjN(HSO )Me3 gave carboxylic acids and ultimately CO and HCl forperchoroethylene, trichloroethylene, cA-l,2-dichloroethylene, 1,1-dichloropropene,... 

Alkenes are also oxidized to epoxides hy peracid or peroxyacid (RCO3H), e.g. peroxyhenzoic acid (C6H5CO3H). A peroxyacid contains an extra oxygen atom compared with carboxylic acid, and this extra oxygen is added to the double bond of an alkene to give an epoxide. For example, cyclohexene reacts with peroxyhenzoic acid to produce cyclohexane oxide. 

Alkenes are oxidized to carboxylic acids and/or ketones by ozone (O3) at low temperatures (—78 °C) in methylene chloride, followed by oxidative... 

No cross ozonide was formed from unsymmetrical alkenes. The authors theorized628 that the carbonyl oxide zwitterionic species formed on wet silica gel immediately adds water followed by rapid decomposition of the intermediate hydroxyalkyl hydroperoxide to carboxylic acid and water. It means that water on silica gel acts as participating solvent. In the absence of adsorbed water, rapid recombination of the adsorbed aldehyde and carbonyl oxide due to a favorable proximity effect gives normal ozonide. The low mobility of adsorbed species on the silica surface accounts for the absence of cross ozonides. 

Compared to ozonation of alkenes, much less is known about the ozonation of alkynes,710 which yields 1,2-dicarbonyl compounds, carboxylic acids, and anhydrides. 1,2,3-Trioxolene (91), analogous to 74 in alkene ozonation mechanism (Scheme 9.14), and zwitterionic intermediates (92) were formulated on the basis of IR studies and trapping experiments ... 

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