Ethyl cyclopropanecarboxylate

Azatricyclo[2.2.1.02 6]hept-7-yl perchlorate, 2368 f Azetidine, 1255 Benzvalene, 2289 Bicyclo[2.1.0]pent-2-ene, 1856 2-/ert-Butyl-3-phenyloxaziridine, 3406 3 -Chloro-1,3 -diphenyleyclopropene, 3679 l-Chloro-2,3-di(2-thienyl)cyclopropenium perchlorate, 3388 Cyanocyclopropane, 1463 f Cyclopropane, 1197 f Cyclopropyl methyl ether, 1608 2,3 5,6-Dibenzobicyclo[3.3.0]hexane, 3633 3,5 -Dibromo-7-bromomethy lene-7,7a-dihy dro-1,1 -dimethyl-1H-azirino[l,2-a]indole, 3474 2.2 -Di-tert-butyl-3.3 -bioxaziridinc, 3359 Dicyclopropyldiazomethane, 2824 l,4-Dihydrodicyclopropa[ >, g]naphthalene, 3452 iV-Dimethylethyl-3,3-dinitroazetidine, 2848 Dinitrogen pentaoxide, Strained ring heterocycles, 4748 f 1,2-Epoxybutane, 1609 f Ethyl cyclopropanecarboxylate, 2437 2,2 -(l,2-Ethylenebis)3-phenyloxaziridine, 3707 f Methylcyclopropane, 1581 f Methyl cyclopropanecarboxylate, 1917 f Oxetane, 1222... 

Ethyl 2-cyano-2-( 1 -//-tetrazol-5-ylhydrazono)acetate, 2352 f Ethylcyclobutane, 2452 f Ethylcyclopentane, 2846 f Ethyl cyclopropanecarboxylate, 2431 f Ethylcyclopropane, 1935... 

Di-ferf-butyl-3,3 -bioxaziridine, 3353 Dicyclopropyldiazomethane, 2820 1,4-Dihydrodicyclopropa[/ ,g]naphthalene, 3446 /V-Dimethylethyl-3,3-dinitroazetidine, 2844 Dinitrogen pentaoxide, Strained ring heterocycles, 4743 f 1,2-Epoxybutane, 1604 f Ethyl cyclopropanecarboxylate, 2431 2,2 -(l,2-Ethylenebis)3-phenyloxaziridine, 3700 f Methyl cyclopropanecarboxylate, 1911 f Methylcyclopropane, 1576... 

With its low yield of 40 % entry 1 is exceptional, since in this case very likely missing steric hindrance causes considerable self condensation diming enolate generation 69). This process has been reported as the exclusive reaction in attempts to deprotonate the unsubstituted ethyl cyclopropanecarboxylate 70). Decreased CH-acidity of the starting material and increased reactivity of the corresponding enolate — both caused by I-strain in the intermediate71) — should be responsible for this self condensation. It proceeds in the deprotonation phase, if not prevented by additional substituents as in almost all other cases in Table 3. 

This conclusion had to be revised when Piehl and Brown showed that although they were able to repeat Haller s work on the alkylation of phenylcyclopropyl ketone (199) by means of sodium amide and methyl iodide to give 200 (a reaction which they thought was wrong), unexpected reactions occurred in the case of ethyl cyclopropanecarboxylate (201). With sodium amide the amide (202), and with triphenylmethyl sodium the ketone (203) is formed. The latter reaction is normally typical of esters having no a-hydrogen atom ... 

In addition, 238 was found which is undoubtedly the result of a two-step Claisen-aldol sequence. The formation of 238 has been confirmed by Seebach and coworkers . This clearly indicates that the anion of ethyl cyclopropanecarboxylate is formed by the action of LDA on 235, but that the anion is very reactive in agreement with the low acidity of 235. When trityllithium reacted with 235 only 238 was obtained after quenching with AcOD. Potassium hydride together with several trapping reagents gave neither 238 nor the expected trapping products. 

Ethyl cyclopropanecarboxylate reacted with dimethylaluminum methylselenolate, prepared by refluxing a toluene solution of trimethylaluminum with powdered selenium, to give Sc-methyl cyclopropanecarboselenoate in 96% yield. 

Methyl and ethyl cyclopropanecarboxylates readily afford (dialkyl)(cyclopropyl)methanols on treatment with alkyllithium and alkyl Grignard reagents. Lithium reagents have been used... 

Aluminum trichloride is able to convert ethyl cyclopropanecarboxylate (8) into a bifunctional electrophile that undergoes Friedel-Crafts reactions. When this reaction was carried out in boiling benzene, 2-methyl-l-indanone (9, R = H) was obtained in excellent yield.The aluminum trichloride catalyzed reaction of cyclopropylcarboxylic acid chloride with benzene led to a mixture of 2- and 3-methylindanones. ... 

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