Cyclopropanation of olefins with diazoalkanes, catalyzed by Co-II(porphyrin) complexes : A synthetic and mechanistic investigation and the molecular structure of Co-III(TPP)(CH2CO2Et) (TPP = dianion of meso-tetraphenylporphyrin)
Articolo
Data di Pubblicazione:
2003
Citazione:
Cyclopropanation of olefins with diazoalkanes, catalyzed by Co-II(porphyrin) complexes : A synthetic and mechanistic investigation and the molecular structure of Co-III(TPP)(CH2CO2Et) (TPP = dianion of meso-tetraphenylporphyrin) / A. Penoni, R. Wanke, S. Tollari, E. Gallo, D. Musella, F. Ragaini, F. Demartin, S. Cenini. - In: EUROPEAN JOURNAL OF INORGANIC CHEMISTRY. - ISSN 1434-1948. - :7(2003), pp. 1452-1460.
Abstract:
Cobalt(II) porphyrin complexes catalyze reactions between ethyl diazoacetate (EDA) and styrenes to give the corresponding cyclopropanes with trans selectivity. The reactions of other diazoalkanes and other olefins have also been carried out, and the mechanism of the reaction has been investigated. Kinetic data and stoichiometric reactions support the formation of a diazoalkane cobalt-porphyrin complex that reacts with the olefins to generate the cyclopropane. Diethyl maleate and fumarate are not formed in the presence of an excess of olefin. On treatment of EDA with Co-II(TPP) (TPP = dianion of meso-tetraphenylporphyrin) in the absence of the olefin, an alkyl cobalt(III) complex Co-III(TPP)(CH2CO2Et) was isolated, and its structure has been solved by X-ray diffraction.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
cobalt; cyclopropanation; olefins; porphyrinoids
Elenco autori:
A. Penoni, R. Wanke, S. Tollari, E. Gallo, D. Musella, F. Ragaini, F. Demartin, S. Cenini
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