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Titolo:
DEVELOPMENT OF MULTIFUNCTIONAL ASYMMETRIC CATALYSTS AND THEIR APPLICATION TO PRACTICAL ORGANIC-SYNTHESIS
Autore:
SHIBASAKI M; IIDA T; YAMADA YMA;
Indirizzi:
UNIV TOKYO,GRAD SCH PHARMACEUT SCI,BUNKYO KU,7-3-1 HONGO TOKYO 1130033 JAPAN
Titolo Testata:
Yuki Gosei Kagaku Kyokaishi
fascicolo: 5, volume: 56, anno: 1998,
pagine: 344 - 356
SICI:
0037-9980(1998)56:5<344:DOMACA>2.0.ZU;2-T
Fonte:
ISI
Lingua:
JPN
Soggetto:
NITROALDOL REACTION; STRYCHNOS ALKALOIDS; BINOL COMPLEXES; UNFUNCTIONALIZED OLEFINS; EFFICIENT SYNTHESIS; CORE STRUCTURE; EPOXIDATION; REAGENT; ACID; PHOSPHONATES;
Keywords:
ALUMINUM; ASYMMETRIC CATALYSIS; ALDOL REACTION; BIMETALLIC COMPLEX; EPOXIDE; EPOXIDATION; GALLIUM; HETEROBIMETALLIC; LANTHANIDE; MULTIFUNCTIONAL COMPLEX;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
73
Recensione:
Indirizzi per estratti:
Citazione:
M. Shibasaki et al., "DEVELOPMENT OF MULTIFUNCTIONAL ASYMMETRIC CATALYSTS AND THEIR APPLICATION TO PRACTICAL ORGANIC-SYNTHESIS", Yuki Gosei Kagaku Kyokaishi, 56(5), 1998, pp. 344-356

Abstract

This article focuses on a new concept in catalytic asymmetric synthesis, which was first realized by the use of heterobimetallic complexes. As such complexes function at the same time as both a Lewis acid and a Bronsted base, similar to enzymes, they make possible a variety of efficient catalytic asymmetric reactions. This ''heterobimetallic'' concept has proven to be applicable to a variety of new asymmetric catalyses. We have already succeeded in asymmetric nitroaldol reactions catalyzed by the LaLi(3)tris (binaphthoxide) complex (LLB) and asymmetric Michael reactions catalyzed by the LaNa(3)tris (binaphthoxide) complex(LSB). Now the LLB catalyst could also be applied efficiently to the tandem inter-intramolecular asymmetric nitroaldol reaction, affording a synthetically useful bicyclic product with four newly generated chiral carbons in one pot. Furthermore we succeeded in the first direct asymmetric aldol reactions of aldehydes with unmodified ketones (up to 94% ee) by using a catalytic amount of LLB. While LLB was also effective in the hydrophosphonylation of aldehydes, asymmetric hydrophosphonylations of imines were efficiently catalyzed by the LnK(3)tris (binaphthoxide) complex (LnPB:Ln=rare earth metal such as La, Yb) (up to 96% ee). On the other hand, alkali metal free lanthanum complexes prepared from Ln(O-i-Pr)(3) (Ln=La or Yb) and 1,1'-binaphthol (BINOL) or 3-hydroxymethyl-BINOL were excellent catalysts for the asymmetric epoxidation of alpha,beta-unsaturated ketones (up to 94% eel. We also developed another type of heterobimetallic catalysts featuring group 13 elementssuch as Al or Ga as a central metal. Among them, the AlLibis(binaphthoxide) complex (ALB) is an effective catalyst for asymmetric Michael reactions of malonates or Horner-Wadsworth-Emmons reagents (up to 99% ee) and for asymmetric tandem Michael-aldol reactions. Applications bi this catalyst to syntheses of biologically important compounds such as11-deoxy-PGF(1 alpha) and tubifolidine are also described. Furthermore the GaLibis (binaphthoxide) complex (GaLB) in combination with molecular sieves 4 A was found to be an efficient catalyst for asymmetric ring openings of a variety of epoxides with t-BuSH (up to 97% ee).

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/11/20 alle ore 18:06:31