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Michael Additions Catalyzed by Bifunctional Mesoporous Silica
A. Puglisi*, R. Annunziata, M. Benaglia*, F. Cozzi, A. Gervasini, V. Bertacche, M. C. Sala
Università degli Studi di Milano, Italy
23 March 2009 (online)
The Michael reaction mediated by mesoporous silica-supported amine-urea bifunctional catalysts is reported in which the tertiary amine and the urea moieties work as a base and an acid, respectively. The reaction of acetylacetone (6) with 2-nitrostyrene (7) was carried out with bifunctional catalyst 1 (amine/urea = 53:47) under conditions A to give 3-[1-(1-phenyl-2-nitroethyl)]-2,4-pentadione (8) in 80% yield. When catalysts 2-5 were used, product 8 was obtained in 0-56% yield. Catalyst 1 was reused three times under conditions B to afford product 8 in high yields.