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Titolo:
SELF-ASSEMBLY OF HETEROBIMETALLIC COMPLEXES AND REACTIVE NUCLEOPHILES- A GENERAL STRATEGY FOR THE ACTIVATION OF ASYMMETRIC REACTIONS PROMOTED BY HETEROBIMETALLIC CATALYSTS
Autore:
ARAI T; YAMADA YMA; YAMAMOTO N; SASAI H; SHIBASAKI M;
Indirizzi:
UNIV TOKYO,FAC PHARMACEUT SCI,BUNKYO KU TOKYO 113 JAPAN
Titolo Testata:
Chemistry
fascicolo: 11, volume: 2, anno: 1996,
pagine: 1368 - 1372
SICI:
0947-6539(1996)2:11<1368:SOHCAR>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
NITROALDOL REACTION; BINOL COMPLEXES; ALPHA,BETA-UNSATURATED KETONES; EFFICIENT SYNTHESIS; MICHAEL ADDITION;
Keywords:
HETEROBIMETALLIC CATALYSTS; MICHAEL ADDITIONS; MULTIFUNCTIONAL CATALYSTS; NITROALDOL REACTIONS; SELF-ASSEMBLY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
18
Recensione:
Indirizzi per estratti:
Citazione:
T. Arai et al., "SELF-ASSEMBLY OF HETEROBIMETALLIC COMPLEXES AND REACTIVE NUCLEOPHILES- A GENERAL STRATEGY FOR THE ACTIVATION OF ASYMMETRIC REACTIONS PROMOTED BY HETEROBIMETALLIC CATALYSTS", Chemistry, 2(11), 1996, pp. 1368-1372

Abstract

Heterobimetallic asymmetric catalysts, such as the lanthanum-lithium-binaphthol complex (LaLi-BINOL), the aluminum-lithium-binaphthol complex (AlLi-BINOL), and a newly prepared gallium-sodium-binaphthol complex (GaNa-BINOL), have been self-assembled with reactive nucleophiles, such as lithium nitronates and sodium malonates, to generate more efficient catalysts than the parent heterobimetallic catalysts. For example, by the combined use of LaLi-BINOL (1 mol %; contains one H2O molecule) and BuLi (0.9 mol%) as the catalyst system, asymmetric nitroaldol reactions are greatly accelerated in all cases without a decrease in the optical purity of the nitroaldol products. Kinetic analyses have also been carried out on the GaNa-BIhTOL-catalyzed Michael reaction of dibenzyl malonate with cyclohexenone, with or without NaOtBu. The calculated rate constants show that the combined use of GaNa-BINOL and NaOtBu as the catalyst gives reaction rates that are about 50 times faster than with GaNa-BINOL alone. This activation method should be useful for other asymmetric reactions catalyzed by heterobimetallic complexes.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/11/20 alle ore 14:04:42