Surface confinement effects on enantioselective cyclopropanation. Reactions with supported chiral 8-oxazolinylquinoline-copper complexes
- Fraile, J.M. 1
- García, J.I. 1
- Jiménez-Osés, G. 1
- Mayoral, J.A. 1
- Roldán, M. 1
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1
Instituto de Nanociencia y Materiales de Aragón
info
ISSN: 0276-7333
Datum der Publikation: 2008
Ausgabe: 27
Nummer: 10
Seiten: 2246-2251
Art: Artikel
Andere Publikationen in: Organometallics
Zusammenfassung
Chiral quinolinoxazoline ligands, a class of C1-symmetric chiral ligands, are tested in the enantioselective supported catalysis of a cyclopropanation reaction, trying to improve surface confinement effects of the clay support on the reaction stereoselectivity. In the case of trans/cis diastereoselectivity, these surface effects lead to a complete reversal of selectivity, with cis selectivity values superior to those previously found using C2-symmetryic bisoxazoline ligands. On the other hand, the enantioselectivities do not display important variations in the supported catalysts. A theoretical (DFT) mechanistic study is carried out to explain the origin of the enantioselectivity in homogeneous phase at a molecular level. © 2008 American Chemical Society.