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Titolo:
A possible mechanism for enantioselectivity in the chiral epoxidation of olefins with [Mn(salen)] catalysts
Autore:
Jacobsen, H; Cavallo, L;
Indirizzi:
Univ Naples Federico II, Dipartimento Chim, I-80126 Naples, Italy Univ Naples Federico II Naples Italy I-80126 Chim, I-80126 Naples, Italy Univ Zurich, Inst Anorgan Chem, CH-8057 Zurich, Switzerland Univ Zurich Zurich Switzerland CH-8057 Chem, CH-8057 Zurich, Switzerland
Titolo Testata:
CHEMISTRY-A EUROPEAN JOURNAL
fascicolo: 4, volume: 7, anno: 2001,
pagine: 800 - 807
SICI:
0947-6539(20010216)7:4<800:APMFEI>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-DYNAMICS SIMULATIONS; PROPENE POLYMERIZATION; IRON PORPHYRINS; COMBINED QM/MM; FORCE-FIELD; COMPLEXES; ENERGY; REGIOSPECIFICITY; APPROXIMATION; SYSTEMS;
Keywords:
asymmetric catalysis; density functional calculations; epoxidations; homogeneous catalysis; molecular modeling;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Cavallo, L Univ Naples Federico II, Dipartimento Chim, Complesso Monte S Angelo,Via Cintia, I-80126 Naples, Italy Univ Naples Federico II Complesso Monte S Angelo,Via Cintia Naples Italy I-80126
Citazione:
H. Jacobsen e L. Cavallo, "A possible mechanism for enantioselectivity in the chiral epoxidation of olefins with [Mn(salen)] catalysts", CHEM-EUR J, 7(4), 2001, pp. 800-807

Abstract

The origin of enantioselectivity in the Jacobsen-Katsuki reaction has beeninvestigated by applying density functional calculations in combination with molecular mechanics methodologies. The calculations suggest that a high enantiomeric excess is connected to three specific features: 1) a chiral diimine bridge. which induces folding of the salen ligand(H(2)salen= bis(salicylidene)ethylenediamine). and hence the formation of a chiral pocket; 2) bulky groups at the 3,3'-positions of the salen ligand, which cause a preferential approach from the side of the aromatic rings; and 3) pi conjugation of the olefinic double bond, which confers regioselectivity and, consequently, enantioselectivity. In combination with experimental studies, the modelalso provides a rationale for the decrease in ee values when one of these components is missing.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/06/20 alle ore 23:55:37