The Knoevenagel condensation of aldose sugars with β-dicarbonyl compounds produces furan derivatives having polyhydroxyalkylated alkyl side chains; this reaction is known as the Garcia Gonzalez reaction. Despite the fact that these polyhydroxyalkyl furans are interesting scaffolds for synthetic chemists to utilize in the synthesis of a variety of biologically interesting molecules, the reported approach suffers from harsh conditions. The development of a general and more efficient protocol is of considerable importance, and in this manuscript, we wish to explore the role of the NaI in enhancing the activity of CeCl3.7H2O as a useful water-tolerant Lewis acid promoter for the Garcia Gonzalez reaction. The procedure proceeds with good yields at 50 °C using our system supported on SiO2 in solvent-free conditions and represents a simple and convenient methodology for the preparation of densely functionalized molecules.
SiO2-Supported CeCl3-7H(2)O-NaI Lewis acid promoter: Investigation into the Garcia Gonzalez reaction in solvent-free conditions
GUNNELLA, Roberto;MARCANTONI, Enrico;
2007-01-01
Abstract
The Knoevenagel condensation of aldose sugars with β-dicarbonyl compounds produces furan derivatives having polyhydroxyalkylated alkyl side chains; this reaction is known as the Garcia Gonzalez reaction. Despite the fact that these polyhydroxyalkyl furans are interesting scaffolds for synthetic chemists to utilize in the synthesis of a variety of biologically interesting molecules, the reported approach suffers from harsh conditions. The development of a general and more efficient protocol is of considerable importance, and in this manuscript, we wish to explore the role of the NaI in enhancing the activity of CeCl3.7H2O as a useful water-tolerant Lewis acid promoter for the Garcia Gonzalez reaction. The procedure proceeds with good yields at 50 °C using our system supported on SiO2 in solvent-free conditions and represents a simple and convenient methodology for the preparation of densely functionalized molecules.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
