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Titolo:
A NEW AND HIGHLY EFFICIENT ASYMMETRIC ROUTE TO CYCLIC ALPHA-AMINO PHOSPHONATES - THE FIRST CATALYTIC ENANTIOSELECTIVE HYDROPHOSPHONYLATION OF CYCLIC IMINES CATALYZED BY CHIRAL HETEROBIMETALLIC LANTHANOID COMPLEXES
Autore:
GROGER H; SAIDA Y; SASAI H; YAMAGUCHI K; MARTENS J; SHIBASAKI M;
Indirizzi:
UNIV OLDENBURG,DEPT CHEM,POB 2503 D-26111 OLDENBURG GERMANY UNIV OLDENBURG,DEPT CHEM D-26111 OLDENBURG GERMANY UNIV TOKYO,GRAD SCH PHARMACEUT SCI,BUNKYO KU TOKYO 1130033 JAPAN CHIBA UNIV,CTR CHEM ANAL,INAGE KU CHIBA 263 JAPAN
Titolo Testata:
Journal of the American Chemical Society
fascicolo: 13, volume: 120, anno: 1998,
pagine: 3089 - 3103
SICI:
0002-7863(1998)120:13<3089:ANAHEA>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
AROMATIC-ALDEHYDES; MASS-SPECTROMETRY; ELECTROSPRAY IONIZATION; ACID-DERIVATIVES; PHOSPHORUS-ACID; BINOL COMPLEXES; INHIBITORS; REAGENTS; EPOXIDATION; MECHANISM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
74
Recensione:
Indirizzi per estratti:
Citazione:
H. Groger et al., "A NEW AND HIGHLY EFFICIENT ASYMMETRIC ROUTE TO CYCLIC ALPHA-AMINO PHOSPHONATES - THE FIRST CATALYTIC ENANTIOSELECTIVE HYDROPHOSPHONYLATION OF CYCLIC IMINES CATALYZED BY CHIRAL HETEROBIMETALLIC LANTHANOID COMPLEXES", Journal of the American Chemical Society, 120(13), 1998, pp. 3089-3103

Abstract

The catalytic and enantioselective hydrophosphonylation of cyclic imines is described for the first time. In addition, we have uncovered a new and highly efficient asymmetric approach to cyclic cc-amino phosphonates using thiazolines as the imine model component. The desired pharmaceutically interesting phosphonates 5a-e could be synthesized by a heterobimetallic (R)-LnPB-catalyzed (Ln = lanthanoid metal, P = potassium, B = (R)=binaphthol) hydrophosphonylation of the C=N double bond with up to 98% enantiomeric excess and up to 98% chemical yield. Using other types of organometallic catalysts (titanium-(IV) complexes), thereaction proceeds with modest enantioselectivity. A detailed investigation concerning the dependence of enantioselectivity and chemical yield, respectively, on a series of reaction parameters (e.g.; lanthanoidand alkali metal, solvent, reaction temperature, pressure, and catalytic amount) is reported. An optimized catalytic lanthanoid system ''(R)-YbPB (5 mol %)/50 degrees C/48 h/THF-toluene (1:7)'' was found. The catalytically active complex was isolated and analyzed by spectroscopic methods. In addition, P-31 and H-1 NMR spectroscopic and LDI-TOF mass spectrometric investigations were carried out to support a postulated mechanistic course for this (R)-LnPB-complex-catalyzed hydrophosphonylation reaction.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 04:10:09