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Titolo:
Medium-sized cyclophanes. Part 57. Synthesis, conformations and stereodynamics of [2.n]metacyclophan-1-enes and their conversion to [2.n]metacyclophan-1-ynes
Autore:
Yamato, T; Fujita, K; Abe, T; Tsuzuki, H;
Indirizzi:
Saga Univ, Fac Sci & Engn, Dept Appl Chem, Saga 8408502, Japan Saga Univ Saga Japan 8408502 & Engn, Dept Appl Chem, Saga 8408502, Japan Tohwa Univ, Tohwa Inst Sci, Minami Ku, Fukuoka 8158510, Japan Tohwa Univ Fukuoka Japan 8158510 Sci, Minami Ku, Fukuoka 8158510, Japan
Titolo Testata:
NEW JOURNAL OF CHEMISTRY
fascicolo: 5, volume: 25, anno: 2001,
pagine: 728 - 736
SICI:
1144-0546(2001)25:5<728:MCP5SC>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
LOW-VALENT TITANIUM; CONVENIENT SYNTHESIS; COUPLING REACTIONS; METACYCLOPHANES; BROMINATION; REDUCTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
61
Recensione:
Indirizzi per estratti:
Indirizzo: Yamato, T Saga Univ, Fac Sci & Engn, Dept Appl Chem, Honjo Machi 1, Saga 8408502, Japan Saga Univ Honjo Machi 1 Saga Japan 8408502 Saga 8408502, Japan
Citazione:
T. Yamato et al., "Medium-sized cyclophanes. Part 57. Synthesis, conformations and stereodynamics of [2.n]metacyclophan-1-enes and their conversion to [2.n]metacyclophan-1-ynes", NEW J CHEM, 25(5), 2001, pp. 728-736

Abstract

anti- and syn-[2.8]Metacyclophan-1-enes 3a, which are both conformationally rigid structures, were prepared in good yields by a McMurry cyclization of 1,8-bis(5-tert-butyl-3-formyl-2-methoxyphenyl)octane 2a. Similarly, McMurry cyclization of 1,10-bis(5-tert-butyl-2-methoxy-3-formylphenyl)decane 2b afforded (E)- and (Z)-[2.10]-metacyclophan-1-enes 3b in good yields. The assignment of the E and Z structures was confirmed by H-1-NMR analyses and single crystal X-ray diffraction studies. Bromination of (E)- and (Z)-3b withbenzyltrimethyl- ammonium tribromide affords exclusively the cis-adduct 4bto the bridged double bond. When treated with potassium tert-butoxide in refluxing HOBut at 80 degreesC for 3 h, bromine adduct meso-4b gave the dehydrobrominated product [2.10]metacyclophan-1-yne 6b in 93% yield, along with1-bromo[2.10]metacyclophan-1-ene 5b in 7% yield; the same reaction with the bromine adduct dl-4b gave 29% 6b along with 5b in 71% yield. Similarly, anti- and syn-[2.8]metacyclophan-1-ynes 6a were also prepared by brominationof syn-[2.n]metacyclophan-1-ene syn-3a, followed by the dehydrobrominationof the bromine adduct. The characterization and the reaction pathway of these products are discussed. The dynamics of the ring inversion and UV spectra are also presented.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/06/20 alle ore 01:55:08