Non-covalent immobilization of chiral copper complexes on Al-MCM41: Effect of the nature of the ligand
Cu-Al-MCM41, prepared by deposition of copper(II) triflate with incipient wetness impregnation and thermal treatment under air flow, can be modified with different chiral ligands of the bis(oxazoline) family. The efficiency of the supported chiral catalysts in the enantioselective cyclopropanation o...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/154923 |
| Acceso en línea: | http://hdl.handle.net/10261/154923 |
| Access Level: | acceso abierto |
| Palabra clave: | Copper Immobilized catalysts Mesoporous materials Bis(oxazolines) Cyclopropanation Asymmetric catalysis |
| Sumario: | Cu-Al-MCM41, prepared by deposition of copper(II) triflate with incipient wetness impregnation and thermal treatment under air flow, can be modified with different chiral ligands of the bis(oxazoline) family. The efficiency of the supported chiral catalysts in the enantioselective cyclopropanation of styrenes with ethyl diazoacetate depends on the nature of the ligand. The azabis(oxazolines) perform much better than the bis(oxazolines) and give stable catalysts that can be used for at least five consecutive runs, with productivities that can reach values close to 1000 molecules of cyclopropane per copper site. The best enantioselectivities obtained with these catalysts are in the range of 60-70% ee in the reaction at 90 °C. |
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