Heterogeneous single site catalysts in many cases show superior performances in terms of activity, selectivity and reciclability coupling together the advantages of heterogeneous and homogeneous systems [1]. Cu(I) complexes (see fig. 1), based on functionalised pyridine-containing macrocyclic chiral ligands [2] were heterogeneized on mesoporous ordered and non-ordered silicas (Davisil, MCM-41, etc.) by the SHB method [3] and they were successfully applied to asymmetric cyclopropanation reactions. Materials obtained were fully characterized for metal content, textural properties, hydrogen bonds between Cu complex and surface silanols by a pool of techniques. Catalysts were tested in asymmetric cyclopropanation of olefins employing ethyldiazoacetate (EDA) as carbene precursor and in the Henry or nitro-aldol reaction and they show performances at least comparable to those obtained with the homogeneous counterpart. Tests using both basic and ordered silicas with the aim of exploiting the confinement effect on stereoselectivity are currently in progress. References [1] V. Dal Santo, F. Liguori, C. Pirovano and M. Guidotti, Molecules accepted for publication [2] A. Caselli, F. Cesana, E. Gallo, N. Casati, P. Macchi, M. Sisti, G. Celentano and S. Cenini, Dalton Trans., 2008, 4202–4205. [3] C. Bianchini, P. Barbaro, V. Dal Santo, R. Gobetto, A. Meli, W. Oberhauser, R. Psaro and F. Vizza, Adv. Synth. Catal., 2001, 343, 41-45. Aknowledgents EU through IDECAT Network of Excellence, European Community’s Sixth Framework Programme (contract NMP3-CT-2005-011730) and NANO-HOST “Homogeneous Supported Catalyst Technologies: the sustainable approach to highly-selective, fine chemicals production” Initial Training Network -The People Program Project no. 215193-2, and MIUR through the project “ItalNanoNet” (Rete Nazionale di Ricerca sulle Nanoscienze; prot. no. RBPR05JH2P) are gratefully acknowledged for financial support.
Staightforward heterogeneization of chiral Cu(I) complexes and their applications to Henry and cyclopropanation reactions / V. Dal Santo, Y. Hönemann, A. Caselli, B. Castano, A. Galarneau, R. Psaro. ((Intervento presentato al 16. convegno Congresso Nazionale di Catalisi tenutosi a Palermo nel 2010.
Staightforward heterogeneization of chiral Cu(I) complexes and their applications to Henry and cyclopropanation reactions
A. Caselli;B. Castano;
2010
Abstract
Heterogeneous single site catalysts in many cases show superior performances in terms of activity, selectivity and reciclability coupling together the advantages of heterogeneous and homogeneous systems [1]. Cu(I) complexes (see fig. 1), based on functionalised pyridine-containing macrocyclic chiral ligands [2] were heterogeneized on mesoporous ordered and non-ordered silicas (Davisil, MCM-41, etc.) by the SHB method [3] and they were successfully applied to asymmetric cyclopropanation reactions. Materials obtained were fully characterized for metal content, textural properties, hydrogen bonds between Cu complex and surface silanols by a pool of techniques. Catalysts were tested in asymmetric cyclopropanation of olefins employing ethyldiazoacetate (EDA) as carbene precursor and in the Henry or nitro-aldol reaction and they show performances at least comparable to those obtained with the homogeneous counterpart. Tests using both basic and ordered silicas with the aim of exploiting the confinement effect on stereoselectivity are currently in progress. References [1] V. Dal Santo, F. Liguori, C. Pirovano and M. Guidotti, Molecules accepted for publication [2] A. Caselli, F. Cesana, E. Gallo, N. Casati, P. Macchi, M. Sisti, G. Celentano and S. Cenini, Dalton Trans., 2008, 4202–4205. [3] C. Bianchini, P. Barbaro, V. Dal Santo, R. Gobetto, A. Meli, W. Oberhauser, R. Psaro and F. Vizza, Adv. Synth. Catal., 2001, 343, 41-45. Aknowledgents EU through IDECAT Network of Excellence, European Community’s Sixth Framework Programme (contract NMP3-CT-2005-011730) and NANO-HOST “Homogeneous Supported Catalyst Technologies: the sustainable approach to highly-selective, fine chemicals production” Initial Training Network -The People Program Project no. 215193-2, and MIUR through the project “ItalNanoNet” (Rete Nazionale di Ricerca sulle Nanoscienze; prot. no. RBPR05JH2P) are gratefully acknowledged for financial support.
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