We have recently reported that copper(I) complexes of the new C1-symmetric pyridine-based 12-membered tetraaza macrocycles, Pyridine Containing Ligands (Pc-L*), are competent catalysts in the asymmetric cyclopropanation. In order to improve our catalytic system Cu(I) complexes based on Pc-L* ligands were heterogeneized on mesoporous ordered and non-ordered silicas (Davisil, MCM-41, etc.) by the Supported by HydrogenBond (SHB) method. Supported catalysts C were tested in enantioselective cyclopropanation in batch conditions showing good catalytic activities of differently substituted olefins employing ethyl diazoacetate (EDA) as carbene precursor in n-hexane. The silica support has a strong influence on the diastereoselective outcome of the reaction, favoring the formation of the more challenging cis isomer. Then, catalysts C were tested as catalyst for the cyclopropanation reaction under flow conditions focusing our attention on the use of supercritical CO2. As model reaction we chose the cyclopropanation of alfa-methyl styrene with EDA. The catalyst has been located in a reactor while the substrate (alfa-methyl styrene and EDA ) are transported into the reactor dissolved in 1,2-DCE or in supercritical CO2, which simultaneously acts as a transport vector for the products. Under optimised conditions, the catalyst was stable over at least 10 h of continuous flow, without drop in activity or selectivity.

Continuous flow cyclopropanation reactions using Cu(I) complexes of Pc-L* ligands supported on silica as catalysts with carbon dioxide as a carrier / B. Castano, E. Gallo, V. Dal Santo, D.J. Cole Hamilton, A. Caselli. ((Intervento presentato al 20. convegno EuCheMS Conference on Organometallic Chemistry tenutosi a St. Andrews nel 2013.

Continuous flow cyclopropanation reactions using Cu(I) complexes of Pc-L* ligands supported on silica as catalysts with carbon dioxide as a carrier

B. Castano
;
E. Gallo;A. Caselli
Ultimo
2013-07-03

Abstract

We have recently reported that copper(I) complexes of the new C1-symmetric pyridine-based 12-membered tetraaza macrocycles, Pyridine Containing Ligands (Pc-L*), are competent catalysts in the asymmetric cyclopropanation. In order to improve our catalytic system Cu(I) complexes based on Pc-L* ligands were heterogeneized on mesoporous ordered and non-ordered silicas (Davisil, MCM-41, etc.) by the Supported by HydrogenBond (SHB) method. Supported catalysts C were tested in enantioselective cyclopropanation in batch conditions showing good catalytic activities of differently substituted olefins employing ethyl diazoacetate (EDA) as carbene precursor in n-hexane. The silica support has a strong influence on the diastereoselective outcome of the reaction, favoring the formation of the more challenging cis isomer. Then, catalysts C were tested as catalyst for the cyclopropanation reaction under flow conditions focusing our attention on the use of supercritical CO2. As model reaction we chose the cyclopropanation of alfa-methyl styrene with EDA. The catalyst has been located in a reactor while the substrate (alfa-methyl styrene and EDA ) are transported into the reactor dissolved in 1,2-DCE or in supercritical CO2, which simultaneously acts as a transport vector for the products. Under optimised conditions, the catalyst was stable over at least 10 h of continuous flow, without drop in activity or selectivity.
Settore CHIM/03 - Chimica Generale e Inorganica
Continuous flow cyclopropanation reactions using Cu(I) complexes of Pc-L* ligands supported on silica as catalysts with carbon dioxide as a carrier / B. Castano, E. Gallo, V. Dal Santo, D.J. Cole Hamilton, A. Caselli. ((Intervento presentato al 20. convegno EuCheMS Conference on Organometallic Chemistry tenutosi a St. Andrews nel 2013.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/387370
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