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Titolo:
Palladium(II)-catalyzed asymmetric cyclization of (Z)-4 '-acetoxy-2 '-butenyl 2-alkynoates. Role of nitrogen-containing ligands in palladium(II)-mediated reactions
Autore:
Zhang, QH; Lu, XY; Han, XL;
Indirizzi:
Chinese Acad Sci, Shanghai Inst Organ Chem, State Key Lab Organomet Chem, Shanghai 200032, Peoples R China Chinese Acad Sci Shanghai Peoples R China 200032 200032, Peoples R China
Titolo Testata:
JOURNAL OF ORGANIC CHEMISTRY
fascicolo: 23, volume: 66, anno: 2001,
pagine: 7676 - 7684
SICI:
0022-3263(20011116)66:23<7676:PACO('>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
SYNTHETIC MICROBIAL CHEMISTRY; KHAND-TYPE REACTION; CATALYZED ENYNE CYCLOISOMERIZATION; A-FACTOR; ENE REACTION; ENANTIOSELECTIVE SYNTHESIS; STREPTOMYCIN BIOSYNTHESIS; CYCLOADDITION REACTIONS; ABSOLUTE-CONFIGURATION; GAMMA-BUTYROLACTONES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
78
Recensione:
Indirizzi per estratti:
Indirizzo: Lu, XY Chinese Acad Sci, Shanghai Inst Organ Chem, State Key Lab OrganometChem, 354 Fenglin Lu, Shanghai 200032, Peoples R China Chinese Acad Sci 354 Fenglin Lu Shanghai Peoples R China 200032 na
Citazione:
Q.H. Zhang et al., "Palladium(II)-catalyzed asymmetric cyclization of (Z)-4 '-acetoxy-2 '-butenyl 2-alkynoates. Role of nitrogen-containing ligands in palladium(II)-mediated reactions", J ORG CHEM, 66(23), 2001, pp. 7676-7684

Abstract

Pd(OAc)(2) combined with nitrogen-containing ligands (e.g., 2,2'-bipyridine) catalyzed the cyclization of (Z)-4'-acetoxy-2'-butenyl 2-alkynoates (1) in acetic acid to afford the alpha-(Z)-acetoxyalkylidene-beta -vinyl-gamma -butyrolactones (2) with high efficiency and high stereoselectivity. The nitrogen-containing ligands, like halides, served to favor beta -heteroatom elimination over beta -hydride elimination in Pd(II)-mediated reactions. Thegenerality of this ligand effect was probed in both stoichiometric and catalytic reactions. With these results in hand, the catalytic asymmetric protocol was achieved with high enantioselectivity (up to 92% ee) when pymox (pyridyl monooxazoline) or bisoxazoline was used. The absolute configuration of the products and the synthetic utility of this asymmetric transformationwere established through the convenient synthesis of (3S)-(+)-A-factor.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 08:44:38