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Titolo:
Solid-phase synthesis of homogeneous ruthenium catalysts on silica for thecontinuous asymmetric transfer hydrogenation reaction
Autore:
Sandee, AJ; Petra, DGI; Reek, JNH; Kamer, PCJ; van Leeuwen, PWNM;
Indirizzi:
Inst Mol Chem, NL-1018 WV Amsterdam, Netherlands Inst Mol Chem AmsterdamNetherlands NL-1018 WV WV Amsterdam, Netherlands
Titolo Testata:
CHEMISTRY-A EUROPEAN JOURNAL
fascicolo: 6, volume: 7, anno: 2001,
pagine: 1202 - 1208
SICI:
0947-6539(20010316)7:6<1202:SSOHRC>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
COMBINATORIAL LIBRARIES; SITE-ISOLATION; KETONES; COMPLEXES; LIGAND; DISCOVERY; OPTIMIZATION; OXIDATION;
Keywords:
asymmetric catalysis; hydrogen transfer; immobilization ruthenium; solid-phase synthesis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Reek, JNH Inst Mol Chem, Nieuwe Achtergracht 166, NL-1018 WV Amsterdam, Netherlands Inst Mol Chem Nieuwe Achtergracht 166 Amsterdam Netherlands NL-1018 WV
Citazione:
A.J. Sandee et al., "Solid-phase synthesis of homogeneous ruthenium catalysts on silica for thecontinuous asymmetric transfer hydrogenation reaction", CHEM-EUR J, 7(6), 2001, pp. 1202-1208

Abstract

The solid-phase synthesis of new asymmetric transfer hydrogenation catalysts as well as the use of these silica supported systems in batch and flow reactors is reported. The ruthenium complex of NH-benzyl-(1R,2S)-(-)-norephedrine covalently tethered to silica showed a high activity and enantioselectivity in the reduction of acetophenone. In three consecutive batchwise catalytic runs, we obtained ee values 88%. In a continuous flow reactor, a very constant catalytic activity was observed; no catalyst deactivation occurred over a period of one week, This has been ascribed to successful site isolation. Using optimized conditions in this flow reactor, the ee was as highas 90% at 95% conversion, The supported catalysts generally show the same trend in catalyst performance as in solution. The viability of our approachwas further shown in one example, the ruthenium(II) complex of (1S,2R)-(+)-2-amino-1,2-diphenylethanol, for which an enantiomeric excess of 58% was observed, which is nearly three times higher than its homogeneous analogue.

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Documento generato il 04/04/20 alle ore 01:53:28