Methyl cyclohexanecarboxylate

Carbonylation of alcohols to acids, table of examples, 46, 74 Carboxylation, by formic acid, 46, 74 of 2-methylcyclohexanol by formic acid-sulfuric acid to 1-methyl-cyclohexanecarboxylic acid, 46, 72... 

Dimethylamine (8) Methanamine, N-methyl- (9) (124-40-3) Methyl cyclohexanecarboxylate Cyclohexanecarboxylic acid, methyl ester (8, 9) (4630-82-4)... 

In a first example of cyclopropane formation from allylpalladium complexes the reaction of dimeric 7t-allylpalladium chloride (1, R = H) with the enolate of methyl cyclohexanecarboxylate (2) was found to give the normal allylic alkylation product 3 only in low yields ( 20%) if the reaction was carried out in tetrahydrofuran in the presence of triphenylphosphane at room temperature, whereas with triethylamine in hexamethylphosphoramide the cyclopropane product 4 is formed in 70% yield. Deuterium labelling of the allyl moiety indicates that the reaction proceeds via nucleophilic attack of the enolate at the central allylic carbon followed by reductive elimination of the cyclopropane product. 

Treatment of (387) with ozone at — 78°C followed by warming to 25 °C resulted in (388) (48 %), (389) (17%), and (390) (9%). The latter two compounds are considered to arise via a Pummerer rearrangement which is facilitated by the acidifying effect of the carbonyl group on the a-proton. However, with this method (391) is converted into (392) and methyl cyclohexanecarboxylate into (383bX both in yields in excess of 90%. 

Draw the product of the reaction of benzyl pentanoate with LDA in THF at -78 C, when it is subsequently treated with methyl cyclohexanecarboxylate and then hydrolyzed with aqueous acid. 

Problem 9.2. When cyclohexyl methyl ketone is treated with trifluoroperethanoic acid (trilluoroperacetic add, CF3CO3H), the Baeyer-Villiger reaction occurs to yield a product, the and C spectra of which are shown. Given these results and the anticipated migratory aptitude expressed in the series shown above, decide which of the two possible products, cyclohexyl ethanoate (cyclohexyl acetate) or methyl cyclohexanecarboxylate, is obtained. 

Scheme 9.147. A representation of the reaction between the methyl ester of cyclohexanecar-boxylic acid (methyl cyclohexanecarboxylate) with lithium diisopropylamide (LDA) to generate a carbanion on the carbon a- to the carbonyl. The carbanion so formed then acts as a nucleophile toward methyl iodide (CH3I) to yield methyl 1-methylcyclohexanecarboxylate, lithium iodide, and recovered base, diisopropylamine ([(CH3)2CH]2NHj.

Substitution processes focused around the carbonyl group as well as at the carbonyl group are, of course, also possible. Consider the case depicted in item 7 of Table 9.9. As noted immediately above for the intermolecular and intramolecular versions of the Claisen condensation, success depends upon generation of an anion a- to the carbon of the carbonyl. Generation of such anions, particularly at fairly high dilution (where reaction between esters is less likely) with hindered bases, followed by addition of an electrophilic species to the reaction medium, results in overall substitution of the electrophilic species for the proton that was removed. In item 7 of Table 9.9, as shown in Scheme 9.147, the methyl ester of cyclohexanecar-boxylic acid (methyl cyclohexanecarboxylate) does not react with the hindered base (LDA) at the carbon of the carbonyl. Rather, the base removes the proton on the carbon a- to the carbonyl and the carbanion so formed then acts as a nucleophile toward methyl iodide (CH3I). Substitution yields methyl 1-methylcyclohexanecarboxylate, lithium iodide, and recovered base, diisopropylamine [(CH3)2CH]2NH. ... 

Scheme 9.149. A representation of the formation of the Tebbe reagent, titaninm p-chlorobis(r 5-2,4-cyclopentadien-l-yl)(dimethylalnminum)-p-methylene-(9Cl), from dicyclo-pentadienyltitanium dichloride (CpaTiCl ) and trimethylaluminnm Al( 113)3, and its reaction with methyl cyclohexanecarboxylate to produce 1-cyclohexyl-l-methoxyethene.

N -butyllithium in hexane added at -15 to -10° under Ng to a stirred soln. of diisopropylamine in tetrahydrofuran, after 15 min. treated dropwise with a soln. of methyl cyclohexanecarboxylate in tetrahydrofuran, then a fast CO2-stream introduced for 10 min. cyclohexane-1,1-dicarboxylic acid monomethyl ester. Y 97%. F. e. and limitations s. S. Reiffers, H. Wynberg, and J. Strating, Tetrah. Let. 1971, 3001 s. a. A. J. H. Klunder and B. Zwanenburg, ibid. 1972, 2383. 

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