1-cyclopentene-l-carboxylic acid

Autoxidation of cyclohexene is mediated by 812(804)3 to give 1-cyclopentene-l-carboxylic acid in 90-92% yield [232], The selective oxidation of sulfides to sulfoxides is accomplished by Bi(NO3)3, both stoichiometrically [233] and catalytically with air [234]. 

Alkenes are important vehicles for incorporating functionality into a ring. An example is the Michael addition of ammonia to 1-cyclopentene-l-carboxylic acid (7.42) to give 2-aminocyclopentane-l-carboxylic acid (7.43), as a mixture of cis- and rra s-isomers.2 The yield in this particular case was rather low, however. Hydrogenation of cycloalkene carboxylic acid derivatives is a convenient route to the... 

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. 

Hydroxy-2-cyclopentene-l-carboxylic acid, H-136 N-(l- Hydroxycyclopentyl)adenosine, H-137 14-Hydroxydaunomycin, A-58... 

In order to confirm the reactivity and selectivity of lead ruthenates for the oxidation of isolated double bonds, two soluble, unsaturated carboxylic acids were chosen that contain a double bond far removed from the solubilizing carboxylate group. The two olefinic compounds, 1-undecylenic acid and 2-cyclopentene-l-acetic acid were both cleaved at the double bond as shown in Figure 13. 

Cyclopcntcne-l-carboxylic acid, C-00037 2-Cyclopcntcne-l-heptanoic acid, C-00038 2-Cyclopcntcnc-l-nonanoic acid, C-00039 2-Cyclopcntcnc-l-nonanol, C-0(X)40 2-Cyclopcntcnc-l-tridccanoic acid, C-00041 2-Cyclopentenc-1 -tridecanol, C-00042 2-Cyclopentene-6-tridecenoic acid, C-00043 2-Cyclopcntene-9-tridccenoic acid, C-00044 2-Cyclopentcne-l-undecanoic acid, C-00045 15-(2-Cyclopentcnyl)-9-deccnoic acid, C-00046 15-(2-Cyclopentenyl)pentadecanoic acid,... 

Cyclopentene-l-carbonitrile (7.54) also reacted with N-bromosuccinimide to give an allylic bromide, 7.55.27 Subsequent reaction with ammonia displaced the bromine and acid hydrolysis of the nitrile led to 3-aminocyclopentene-l-carboxylic acid, 7.S6. Cyclohexenyl acid derivatives have also been used. Bromination of... 

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). ... 

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). 

Seshadri T., Kettmpt A. S)mthesis and characterization of silica gel ion-exchanger bearing 2-amino-l-cyclopentene-l-dithio-carboxylic acid (ACDA) as chelating compound, Presenius Zeitschrift fiir analytische Chemie 1982 310,1-5. 

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