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Titolo:
Functional chiral hybrid silica gels prepared from (R)- or (S)-binaphthol derivatives
Autore:
Brethon, A; Hesemann, P; Rejaud, L; Moreau, JJE; Man, MWC;
Indirizzi:
Ecole Natl Super Chim Montpellier, CNRS, UMR 5076, Lab Chim Organomet Heterochim Mol & Macromol, F-34296 Montpellier 05, France Ecole Natl Super ChimMontpellier Montpellier France 05 llier 05, France
Titolo Testata:
JOURNAL OF ORGANOMETALLIC CHEMISTRY
fascicolo: 2, volume: 627, anno: 2001,
pagine: 239 - 248
SICI:
0022-328X(20010511)627:2<239:FCHSGP>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
HOST-GUEST COMPLEXATION; OPTICAL-PROPERTIES; AMINO-ACID; BINOL; DIETHYLZINC; RECOGNITION; PRECURSORS; CATALYSTS; ALDEHYDES; RHODIUM;
Keywords:
hybrid silica gels; 2,2 '-dihydroxy-1,1 '-binaphthyl;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Moreau, JJE Ecole Natl Super Chim Montpellier, CNRS, UMR 5076, Lab Chim Organomet Heterochim Mol & Macromol, 8 Rue Ecole Normale, F-34296 Montpellier05, France Ecole Natl Super Chim Montpellier 8 Rue Ecole Normale Montpellier France 05
Citazione:
A. Brethon et al., "Functional chiral hybrid silica gels prepared from (R)- or (S)-binaphthol derivatives", J ORGMET CH, 627(2), 2001, pp. 239-248

Abstract

We describe the synthesis of new functional bis-trialkoxysilylated binaphthol derivatives I-V containing protected OH groups and cyano-, pyridyl- andcarbamate-functionalities starting from optically pure (R)- or (S)-2,2 ' -dihydroxy-1,1 ' -binaphthyl (BINOL) and their subsequent transformation to hybrid silica gels via the sol-gel process. (R)-I was obtained by protection of hydroxyl groups of (R)-6.6 ' -dibromo-BINOL with MEM-chloride, halogenmetal exchange with n-butyllithium and coupling of the metalated (R)-BINOLspecies with chlorotrimethoxysilane. The synthesis of (R)-II, (R)-III, (R)-IV and (R)/(S)-V was realized through silylation of 6,6 ' -dibromo-BINOL derivatives under Heck-reaction conditions using vinyl-triethoxysilane and palladium acetate/tri-o-tolyl phosphine. The sol-gel hydrolysis and polycondensation of the precursors (R)-I-(R)-V led to hybrid organosilicate gels (R)-A-(R)-E incorporating C-2-symmetric chiral binaphthyl moieties. The attached functional groups are preserved after sol-gel transformation. Deprotection of the MEM-BINOL unit of (R)-I was performed following two pathways: in the first case, treatment of the gels (R)-A with a ten-fold excess of zinc bromide, and secondly by hydrolysis polycondensation of (R)-I in the presence of nickel or palladium salts. The solids, consisting of a chiral hybrid network, were characterized by solid state NMR, FTIR, TEM and nitrogen sorption analysis. These materials may open new perspectives for applications in heterogeneous catalysis and molecular recognition. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/10/20 alle ore 05:15:25