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Titolo:
Synthesis of sulfur-containing tricyclic ring systems by means of photoinduced decarboxylative cyclizations
Autore:
Griesbeck, AG; Oelgemoller, M; Lex, J; Haeuseler, A; Schmittel, M;
Indirizzi:
Univ Cologne, Inst Organ Chem, D-50939 Cologne, Germany Univ Cologne Cologne Germany D-50939 rgan Chem, D-50939 Cologne, Germany JST, ERATO, Inoue Photochirogenesis Project, Toyonaka, Osaka 5600085, Japan JST Toyonaka Osaka Japan 5600085 Project, Toyonaka, Osaka 5600085, Japan Univ Gesamthsch Siegen, FB 8, OC Chem Biol 1, D-57068 Siegen, Germany UnivGesamthsch Siegen Siegen Germany D-57068 1, D-57068 Siegen, Germany
Titolo Testata:
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
fascicolo: 10, , anno: 2001,
pagine: 1831 - 1843
SICI:
1434-193X(200105):10<1831:SOSTRS>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
ELECTRON-TRANSFER; PHTHALIMIDE SYSTEM; AMINO-ACIDS; CRYSTAL-STRUCTURE; PHOTOCHEMISTRY; PHOTOCYCLIZATION; DYNAMICS; PHTHALOYLCYSTEINE; CARBOXYLATES; DERIVATIVES;
Keywords:
cyclic voltammetry; cyclizations; decarboxylations; electron transfer; photochemistry; phthalimides; thioethers;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
64
Recensione:
Indirizzi per estratti:
Indirizzo: Griesbeck, AG Univ Cologne, Inst Organ Chem, Greinstr 4, D-50939 Cologne, Germany Univ Cologne Greinstr 4 Cologne Germany D-50939 ne, Germany
Citazione:
A.G. Griesbeck et al., "Synthesis of sulfur-containing tricyclic ring systems by means of photoinduced decarboxylative cyclizations", EUR J ORG C, (10), 2001, pp. 1831-1843

Abstract

The intramolecular and intermolecular photoinduced electron transfer reactions of a series of mercaptoacetic acid and mercaptopropionic acid derivatives were investigated. In the intermolecular series, the phthalimidoalkylsulfanylalkylcarboxylates 1a-j and 2 were transformed into the tricyclic ringsystems 3a-j and 4, respectively, with high regioselectivities. The mercaptoacetic acid and 2-mercaptopropionic acid derived substrates la-g and 2 readily cyclized in good to excellent yields (60-98%) but with low diastereoselectivities (except for 1d), whereas the corresponding 3-mercaptopropionicacid derived substrates 1h-j gave the corresponding tricyclic products 3h-j after prolonged irradiation, but with poor yields (11-20%). The intermolecular version - i.e., photodecarboxylative addition to N-methylphthalimide (5) as electron acceptor - was successful with mercaptoacetic add, and 2-mercaptopropionic acid substrates 6a-c and the addition products 7a-c were obtained in high yields (57-90%). No addition, however, was observed with 3-(methylsulfanyl)propionic acid (6d). The regioselectivity of decarboxylationproceeded in a controlled manner for the mercaptosuccinic acid derivativesin both the intramolecular (with 8a-c) and the intermolecular (with 9) versions. Comparison between sulfur-activated and nonactivated species (13, 15) or irradiation of la under nonactivating conditions showed that the carboxylate anion in the position a to the electron-donating sulfur atom acts asa superior leaving group. This efficiency is drastically reduced for carboxylate anions in the beta position. With the former substrates, the photochemical cyclization proceeds with high product yields. Quantum yield measurements for decomposition (Phi (d) as a measure for cyclization) supported these observations. CV measurements indicated preorientation prior to electron transfer in the intramolecular pathway.

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Documento generato il 25/09/20 alle ore 21:03:19