Cyclooctene-4-carboxylic acid

Intramolecular additions have been observed in the o-allylphenols (448), which on irradiation are converted to the cyclic ethers (449 and 450),393 and in cyclooctene carboxylic acid (451), which affords the lactone (452).394... 

The pyrrolidine enamine of cyclohexanone (IX/1) treated with acrylaldehyde yields the bicyclic compound, IX/2, in 72 % yield in which the pyrrolidine ring has moved. On heating with aqueous base, the methiodide IX/3 was transformed to 4-cyclooctene-carboxylic acid (IX/4) [1], In a similar reaction, but without reorganisation of the substituents, 2-nitrocyclohexanone (IX/5) was... 

Alkylation of 28 with acrolein gives the bicyclic ketone (65), which can be converted to 4-cyclooctene-l-carboxylic acid by the action of base on its methiodide (55a). 

A mixture of 17 g of the methiodide and 32 ml of a 40 % aqueous potassium hydroxide solution is heated with stirring in a flask fitted with a condenser. The heating bath should be kept at 125-130°, and the heating should be continued for 5 hours. The cooled reaction mixture is then diluted with 30 ml of water and washed twice with 25-ml portions of ether. The aqueous layer is cautiously acidified in the cold with concentrated hydrochloric acid to a pH of about 2 and then extracted five times with 25-ml portions of ether. The combined extracts are washed twice with 10% sodium thiosulfate solution and are dried (magnesium sulfate). Removal of the solvent followed by distillation affords about 3 g of 4-cyclooctene-l-carboxylic acid, bp 125-12671-1 mm. The product may solidify and may be recrystallized by dissolution in a minimum amount of pentane followed by cooling in a Dry-Ice bath. After rapid filtration, the collected solid has mp 34-35°. 

The reaction is usually performed at low temperatures, and sometimes water has been used as solvent. For example, cyclooctene is ozonized in the presence of an emulsifier (polyoxyethylated lauryl alcohol) with aqueous alkaline hydrogen peroxide to give a,co-alkanedi-carboxylic acid in one pot (Eq. 3.21).91... 

The reaction has also been applied to the conversion of vinyl bromides into acrylic acids, e.g. 1-bromo- and 1-chlorocyclooctene are converted into cyclooctene-1-carboxylic acid (ca. 98%) [3], 2-chloro-3,3-dimethylbut-l-ene yields 4,4-dimethylpent-2-enoic acid (95%), and tams-cinnamic acid is obtained (85%) from fran.v-p-bromostyrene. cis-p-Bromostyrene produces a mixture of cis- and trans-cinnamic acids in 38 and 42% yields, respectively [3]. In these reactions, benzyltri-ethylammonium chloride cannot be used as the phase-transfer catalyst, as it leads to the production of phenylacetic acid [3]. 

On the basis of theoretical studies by Bach and co-workers,17 it was found that the nucleophilic 71-bond of the alkene attacks the 0-0 cr-bond in an Sn2 fashion with displacement of a neutral carboxylic acid. There are, however, some mechanistic anomalies. For example, a protonated peracid should be a much more effective oxygen transfer agent over its neutral counterpart, but experiments have shown only modest rate enhancements for acid catalysed epoxidation. Early attempts to effect acid catalysis in alkene epoxidation where relatively weak acids such as benzoic acid were employed proved unsuccessful.18 The picture is further complicated by contradictory data concerning the influence of addition of acids on epoxidation rates.19 Trichloroacetic acid catalyses the rate of epoxidation of stilbene with perbenzoic acid, but retards the rate of a double bond containing an ester constituent such as ethyl crotonate.20 Recent work has shown that a seven-fold increase in the rate of epoxidation of Z-cyclooctene with m-chloroperbenzoic acid is observed upon addition of the catalyst trifluoroacetic acid.21 Kinetic and theoretical studies suggest that the rate increase is due to complexation of the peroxy acid with the undissociated acid catalyst (HA) rather than protonation of the peroxy acid. Ab initio calculations have shown that the free energy of ethylene with peroxy-formic acid is lowered by about 3 kcal mol-1 upon complexation with the catalyst.21... 

Phenylseleno-lactonization of 4-cyclooctene-l-carboxylic acid (41) gives a mixture of six- and seven-membered-ring lactones 42 A and 42B by TLC and H-NMR spectroscopy in a 3 1 ratio. After passing through a silica gel column, however, only one product, the six-membered lactone 42 A, is obtained in 94% yield 3. 

To a magnetically stirred solution of 152 mg (1.0 mmol) of 4-cyclooctene-1-carboxylic acid in 5 mL of CHjdj is added 110 mg (1.1 mmol) of F,t3N and the reaction mixture is kept at r.t. for short period. The solution is then cooled to —78 C and solid 212 mg (I.I mmol) of phenylselenenyl chloride is added in one portion. The reaction mixture is stirred at that temperature until completion which is indicated hy the full dissolution of the red-orange selenenyl chloride. The pale-yellow solution is then allowed to reach r.t., concentrated and chromatographed (silica gel, CH, CI2). Removal of the solvent from the appropriate fractions gives the six-membered lactone 42A as colorless crystals yield 94% mp 67 -69 °C. 

Cyclooctene H2SO4 1 -Ethylcyclohexane carboxylic acid higher molecular weight acids (36 64) 45 [991]... 

During the mechanistic studies of estrogen biosynthesis, selective oxidation of androstene-3,17,19-trione (n) to the corresponding carboxylic acid was found to proceed by iron porphyrin complexes (Scheme 14A) [253]. On the basis of substituent effect on the benzaldehyde oxidation and kinetic isotope effect, direct hydrogen abstraction mechanism has been proposed [254]. The relative reactivity of aldehydes and alkenes is as follows cyclooctene, styrene > aldehyde, terminal alkene > a, 3-unsaturated ketone. 

Dry diethyl malonate added to a soln. of Na in abs. ethanol, stirred 20 min. at 50° under N2, 5,6-epoxy-l-cyclooctene added, refluxed 3 days, aq. KOH added, and refluxed 1 hr. 10-oxo-9-oxabicyclo[6.3.0]undec-4-ene-ll-carboxylic acid (Y 70%) stirred 0.5 hr. at 80° with diethylamine and formalin soln., Na-acetate and glacial acetic acid added, and heated 15-30 min. at 80-90° 11-methylene-9-oxabicyclo[6.3.0]undec-4-en-10-one (Y 87%). F. e. s. N. Bensel, H. Marschall, and P. Weyerstahl, B. 108, 2697 (1975). 

If the ozonolysis reaction mixture is treated with an oxidizing agent such as hydrogen peroxide, carboxylic acids rather than aldehydes are produced. For example, the ozonolysis of cyclooctene with an oxidative workup yields octanedioic acid (suberic acid). This compound is one of several dicarbox-yhc acids excreted in large amounts by persons suffering from diabetes. 

Another method that appears to have commercial potential is the ozonolysis of cyclooctene. Ozonolysis is carried out using a short chain carboxyHc acid, preferably propanoic acid, as solvent. The resultant mixture is thermally decomposed in the presence of oxygen at about 100°C to give suberic acid in about 60—78% yield (38—40). Carboxylation of 1,6-hexanediol using nickel carbonyl as catalyst is reported to give suberic acid in 90% yield (41). 

An all-trons structure was assigned to poly(endo,endo-N,N-(norborn-5-ene-2,3-dicarbimido)-L-valine ethyl ester) (Scheme 8.11). Finally, Wagener et al. published details of the formal synthesis of poly(ethylene-co-vinyl alcohol), poly(ethylene-co-vinyl acetate), poly (ethylene-co-methylacrylate) and poly(ethylene-co-acrylic acid) copolymers, obtained via the ROMP of cyclooctene with hydroxy-, acetoxy-, methoxy-carbonyl and carboxylate-functionahzed cyclooctenes, followed by hydrogenation... 

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