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Titolo:
STUDIES DIRECTED TOWARDS THE TOTAL SYNTHESIS OF ANTICAPSIN AND RELATED-COMPOUNDS .4. COMPETITIVE REACTION OF AMINO AND CARBOXY SUBSTITUENTSIN THE HALOHYDRINATION OF 2-AMINOBICYCLO[2.2.2]OCT-5-ENE-2-CARBOXYLICACID-DERIVATIVES
Autore:
CROSSLEY MJ; DAVIES SR; HAMBLEY TW;
Indirizzi:
UNIV SYDNEY,SCH CHEM SYDNEY NSW 2006 AUSTRALIA
Titolo Testata:
Australian Journal of Chemistry
fascicolo: 12, volume: 47, anno: 1994,
pagine: 2221 - 2233
SICI:
0004-9425(1994)47:12<2221:SDTTTS>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
16
Recensione:
Indirizzi per estratti:
Citazione:
M.J. Crossley et al., "STUDIES DIRECTED TOWARDS THE TOTAL SYNTHESIS OF ANTICAPSIN AND RELATED-COMPOUNDS .4. COMPETITIVE REACTION OF AMINO AND CARBOXY SUBSTITUENTSIN THE HALOHYDRINATION OF 2-AMINOBICYCLO[2.2.2]OCT-5-ENE-2-CARBOXYLICACID-DERIVATIVES", Australian Journal of Chemistry, 47(12), 1994, pp. 2221-2233

Abstract

Bromohydrination of benzyl ethylsilyloxybicyclo[2.2.2]oct-5-ene-2-carboxylate (6a) and the (1RS,2RS,4SR)-diastereomer (6b) with N-bromoacetamide in aqueous dioxan has been investigated. These reactions are highly regio- and stereo-selective and give the corresponding bromohydrins (9a) and (9b), but in moderate to low yield. These bromohydrins havethe necessary stereochemistry for conversion into anticapsin. The other products from the reaction are tricyclic compounds formed by capture of the anti-bromonium cation intermediates or resultant bromohydrinsby interaction with the proximal protected carboxy and amino groups within the molecules. Thus the carbolactone (11) is formed from the endo-adduct (6a), and the carbonimidic acid derivative (12) and the cyclic urethane (13) are formed from the exo-adduct (6b). Cleavage of the trimethylsilyl group from the tricyclic compound (12) gives benzyl azatricyclo[5.3.1.0(3,8)]undec-5-ene-7-carboxylate (14), the structure of which was determined by X-ray diffraction methods and refined to a residual of 0.035 for 1549 independent observed reflections. The crystalsof (14) are monoclinic, P2(1)/c, a 12.954(3), b 6.197(3), c 26.784(7)Angstrom, beta 95.33(2)degrees, Z 4. Reactions attempting to generateiodohydrins from the alkenes (6) were also highly regioselective and gave detrimethylsilylateded iodo analogues of (11) and (13).

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/10/20 alle ore 19:06:15