Cyclopentene-3-carboxylic acid esters

The cyclononadiene in (4.72) is obtained by thermal rearrangement of the photoadduct of a cyclobutene carboxylic acid ester and cyclopentene 484). 

Polhni, G.P, Barco, A. and De Giuli, G. (1972) Tetramethylguanidine-catalysed addition of nitromethane to a, P-unsaturated carboxylic acid esters. Synthesis, 44-45 Alvarez, F.S. and Wren, D. (1973) Synthesis of ( )-deoxyprostaglandin Ei, and Fip and its 15P-epimers by conjugate addition of nitromethane to 2-(6 -carbomethoxyhexyl)-2-cyclopenten-l-one. Tetrahedron Letters, 569-572 Hewson, A.T. and MacPherson, D.T. (1983) Conjugate addition to the ethylene ketal of 2-carbomethoxy-2-cyclopentenone a synthesis of sarkomycin. Tetrahedron Letters, 24, 647-648 Naito, T., Honda, Y, Bhavakul, V. et al. (1997) Radical cyclization in heterocycle synthesis. II. Total synthesis of ( )-anantine and ( )-isoanantine. Chemical Pharmaceutical Bulletin, 45, 1932-1939. 

Cyclopentene-l,3-diones from carboxylic acid esters via p-hydroxy-8-sulfinylcarboxylic acid esters and 5-sulfinylcyclopentan-3-olones... 

Coyle has summarized the photochemistry of carboxylic acid derivatives. For arene carboxylic acid esters it has been shown that [2-1-2]-cycloaddition competes with hydrogen abstraction by the excited ester from an allylic position of the alkene. The addition of methyl benzoate 17 to 2-methyl-2-butene gave a 1 1 mixture of the Paterno-Bilchi adduct 18 and the coupling product 19. Less electron-rich alkenes (e.g., cyclopentene) did add preferentially toward the benzene ring of 17 in an ortho- and metacycloaddition manner. Furans could also be added photochemically to methyl benzoate and other aren-ecarboxylic acid esters. The resulting bicyclic oxetanes could be transformed into a series of synthetically valuable products. [2-1-2]-Cycloadducts and/or their cleavage or rearrangement products have also been described for photoreactions of alkenes with diethyl oxalate,benzoic acid, " and carbamates. ... 

A soln. of Na in abs. alcohol cooled to 5°, added to a soln. of ethyl 2-thiocyclo-pentanone-l-carboxylate in abs. ethanol, and the resulting soln. allowed to react with methyl iodide -> ethyl 2-methylmercapto-l-cyclopentene-l-carboxy-late. Y 82%.—In contrast to the 0-analogs where C-substitution prevails, only S-subst. derivatives could be obtained from thiocyclopentanone-2-carboxylic acid esters. F. e., also with K-salts and in benzene, s. R. Mayer and P. Barthel, B.95, 428 (1960). 

Volume 75 concludes with six procedures for the preparation of valuable building blocks. The first, 6,7-DIHYDROCYCLOPENTA-l,3-DIOXIN-5(4H)-ONE, serves as an effective /3-keto vinyl cation equivalent when subjected to reductive and alkylative 1,3-carbonyl transpositions. 3-CYCLOPENTENE-l-CARBOXYLIC ACID, the second procedure in this series, is prepared via the reaction of dimethyl malonate and cis-l,4-dichloro-2-butene, followed by hydrolysis and decarboxylation. The use of tetrahaloarenes as diaryne equivalents for the potential construction of molecular belts, collars, and strips is demonstrated with the preparation of anti- and syn-l,4,5,8-TETRAHYDROANTHRACENE 1,4 5,8-DIEPOXIDES. Also of potential interest to the organic materials community is 8,8-DICYANOHEPTAFULVENE, prepared by the condensation of cycloheptatrienylium tetrafluoroborate with bromomalononitrile. The preparation of 2-PHENYL-l-PYRROLINE, an important heterocycle for the synthesis of a variety of alkaloids and pyrroloisoquinoline antidepressants, illustrates the utility of the inexpensive N-vinylpyrrolidin-2-one as an effective 3-aminopropyl carbanion equivalent. The final preparation in Volume 75, cis-4a(S), 8a(R)-PERHYDRO-6(2H)-ISOQUINOLINONES, il lustrates the conversion of quinine via oxidative degradation to meroquinene esters that are subsequently cyclized to N-acylated cis-perhydroisoquinolones and as such represent attractive building blocks now readily available in the pool of chiral substrates. 

The methyl ester has also been obtained by esterification of cyclopentanecarboxylic acid.8 The acid, in turn, has been prepared by the Favorskii rearrangement,6 7 9-11 by the reaction of cyclopentyl Grignard reagent with carbon dioxide,12 by the carbonylation of cyclopentyl alcohol with nickel carbonyl13 or with formic acid in the presence of sulfuric acid,14 and by the hydrogenation of cyclopentene-1-carboxylic acid prepared from ethyl cyclopentanone-2-carboxylate 15 or from cyclopentanone cyanohydrin.16... 

Irradiation of l,3-bisdiazocyclohexan-2-ones in hydroxylic solvents affords cyclopentene-1-carboxylic acids and esters regiochemical control is only moderate. Although the course of the reactions could be accommodated by sequential Wolff rearrangement and [1,2] H-shift, studies on l,3-bisdiazo-l,3-di-phenylpropan-2-one indicate the formation of the cyclopropenone intermediate (106). ... 

Methyl 3-cyclopentene-1-carboxylate 3-Cyclopentene-1-carboxylic acid, methyl ester (58101-60-3), 75, 197... 

Pyrethrin I, C Hj,03, 2,2 dimethyl-3 (2-methyt-I.pro. penyt)cyclopropanecarboxylic add 2-mcthyl-4-oxt>-3 (2,4-pentadlenytb2 cyclopenten I-y 1 ester, chrysonthemummono-carboxylic acid pyreth rolone ester. R = CH3. Viscous liq-uid. bp,( K 146-150°. 1.5242. [a]g — 14 (isooctane),... 

Cyclopropaneacrylic acid, 3-carboxy-a,2,2-trimethyl-, 1-methyl ester, ester with 4-hydroxy-3-methyl-2-(2,4-pentadienyl)-2-cyclopenten-1-one. See Pyrethrin II Cyclopropane carboxylic acid, 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl-, (2-methyl (1,r-biphenyl)-3-yl) methyl ester, (z)-. See Bifenthrin... 

Treatment of cyclopentene-2-carboxylic acid with performic acid produced approximately equal amounts of the corresponding cis-2,trans-3- and trans-2,cis-3-dihydroxycyclopentane-r-1-carboxylic acids which can be separated chromato-graphically via their methyl esters. The rrans-2,cis-3-compound was cyclized by tosyl chloride to the y-lactone whereas the cis-2jtrans-3-diol gave a trans-3-tosyloxy-P-lactone in an unprecedent reaction for a P-hydroxy-acid. The assignments of configuration and structure are supported by substantial chemical and spectoscopic evidence. 

Esterification. Add-catalyzed esterification of carboxylic acid with alcohol produces water as a coproduct. However, a greener method of esterification of carboxylic acid is via the addition of olefin, which does not produce any co-products and therefore, displays 100% atom efficiency. Proton-exchanged montmorillonite (H+-mont) can be used as a catalyst for addition reactions of carboxylic acids to alkenes (Fig. 7) (38)a). For example, the reaction of benzoic acid with norbomene in the presence of the H+-mont catalyst gave 2-benzoyloxynorbomane. Even with less-reactive simple alkenes, such as cyclopentene and cyclohexene, the corresponding esters were obtained in excellent yields. 

Cl0H10CI2O4 f 2-trans-Ally1-3,5-dichloro-1-hydroxy-4-oxo- 1S,5S)-2-cyclopentene-1-carboxylic acid methyl ester, 34B, 339 C10H12O4, Cantharidin, 43B, 766 C10H12O5, Asperlin, 44B, 542 CioHi3Br04, Jacobine bromodilactone, 28, 560... 

Cyclopropene esters give aminobicyclo[2.1.0]pentane derivatives, which can undergo ring-opening reactions to cyclopentenes For example, methyl 3,3-dimethylcyclo-propene-l-carboxylate (37), obtained by photolysis of the corresponding pyrazolinic derivative, reacted with the diquinanic enamine 36 to give a mixture of the alkylation product 38 and the [2 + 2] cycloadduct 39 which, on acid treatment, was transformed into the triquinanic cyclopentene alcohol 40 (equation 6). 

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