Cyclopentene-3-carboxylic acid synthesis

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. 

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. 

Seshadri, T. Kettrup, A. Synthesis and characterization of silica gel ion-exchanger bearing 2-amino-1-cyclopentene-1-dithio-carboxylic acid (ACDA) as chelating compound. Fresenius Z. Anal. Chem. 1982, 311 (1-2), 18, 1. 

Synthesis of optically active PF-04634817 (271) based on commercially available (-)-Vince Lactam as chirality source. Starting from (-)-Vince Lactam the chiral key 4-amino-2-cyclopentene-l-carboxylic acid derivative 286 was synthesized. The componnd 286 is dimethyl pyrrole protected form of corresponding aminoacid, which was subjected to amide coupling with Boc-protected diamine 287 to give... 

By using a free-radical fragmentation of a-cyclobutyhnethyl radicals, a variety of polycyclic structures can be obtained. When applied to the initial photocycloadduct of a 3-cyclopentenone carboxylic acid with a substituted cyclopentene, a 5—7 ring s) tem can be obtained. This approach was used for a total synthesis of ( )-aUsmol (Scheme 16). 

Asymmetric hydrovinylation of cyclopentadiene is used for the synthesis of 2-cyclopentene-l-tridecanoic acid (8), a chiral natural product containing a cyclopentene ring and a carboxylic group in the carbon side chain5,... 

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