Michael Additions Catalyzed by Bifunctional Mesoporous Silica

Significance

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.