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Titolo:
A CONVERGENT SYNTHETIC ROUTE TO (-DYNEMICIN-A AND ANALOGS OF WIDE STRUCTURAL VARIABILITY())
Autore:
MYERS AG; TOM NJ; FRALEY ME; COHEN SB; MADAR DJ;
Indirizzi:
CALTECH,DIV CHEM & CHEM ENGN PASADENA CA 91125
Titolo Testata:
Journal of the American Chemical Society
fascicolo: 26, volume: 119, anno: 1997,
pagine: 6072 - 6094
SICI:
0002-7863(1997)119:26<6072:ACSRT(>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANTITUMOR ANTIBIOTIC DYNEMICIN; DIRECTED ORTHO METALATION; CROSS-COUPLING REACTION; QUINONE IMINE KETALS; ARYL METHYL ETHERS; THIOETHOXIDE ION; 2-ACYLOXYISOBUTYRYL HALIDES; REGIOSELECTIVE SYNTHESIS; TRIBUTYLTIN HYDRIDE; ADDITION-REACTIONS;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
105
Recensione:
Indirizzi per estratti:
Citazione:
A.G. Myers et al., "A CONVERGENT SYNTHETIC ROUTE TO (-DYNEMICIN-A AND ANALOGS OF WIDE STRUCTURAL VARIABILITY())", Journal of the American Chemical Society, 119(26), 1997, pp. 6072-6094

Abstract

An enantioselective synthetic route to (+)-dynemicin A (1) is described that involves as the key and final step the Diels-Alder cycloaddition of the quinone imine 6 with the isobenzofuran 107 followed by an oxidative workup to provide (+)-1 in 40% yield. The synthetic route begins with the condensation of (-)-menthyl acetoacetate and trans-ethyl crotonate to form the crystalline cyclohexanedione 14, which is then transformed to the enantiomerically pure quinone imine 6 in 23 steps with an average yield of 85% and an overall yield of 2-3%. Key features of this sequence include the coupling of the enol triflate 11 and the arylboronic acid 10 (90%), the thermal deprotection/internal amidation of the coupling product 18 (84%), the use of 2-chloropyridine as an economical alternative to 2,6-di-tert-butylpyridine to promote the reaction of the quinolone 9 and triflic anhydride (85%), the highly stereoselective addition of the (Z)-enediyne 31 to the quinoline 61 (89%), intramolecular acetylide addition within the acetylenic ketone 66 (94%),and oxidation of the phenol 76 with iodosobenzene to afford the quinone imine precursor 77 in 89% yield. Both the quinone imine and isobenzofuran components of the final coupling reaction can be varied, thus providing an ideal route for the preparation of a wide variety of dynemicin analogs.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 08/07/20 alle ore 08:11:11