title: SiO2-supported CeCl3.7H2O-NaI Lewis acid promoter: investigation into the Garcia Gonzalez reaction in solvent-free conditions.
abstract: The Knoevenagel condensation of aldose sugars with beta-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 degrees 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. Furthermore, the first qualitative results obtained on mechanistic investigation on the role of iodide on this our heterogeneous reaction may be of value for optimization of existing organic transformations and for the development of new ones.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Camerino, via S. Agostino 1, I-62032 Camerino (MC), Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Bartoli
authors.forename: José G
authors.initials: JG
authors.lastname: Fernandez-Bolaños
authors.forename: Giustino
authors.initials: G
authors.lastname: Di Antonio
authors.forename: Gioia
authors.initials: G
authors.lastname: Foglia
authors.forename: Sandra
authors.initials: S
authors.lastname: Giuli
authors.forename: Roberto
authors.initials: R
authors.lastname: Gunnella
authors.forename: Michele
authors.initials: M
authors.lastname: Mancinelli
authors.forename: Enrico
authors.initials: E
authors.lastname: Marcantoni
authors.forename: Melissa
authors.initials: M
authors.lastname: Paoletti
mesh_terms: D000143:Acids / Q000737:chemistry*; D002586:Cesium / Q000737:chemistry*; D002625:Chemistry, Organic / Q000379:methods; D002712:Chlorides / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry; D008956:Models, Chemical; D058428:Silica Gel; D012822:Silicon Dioxide / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000143:Acids; D002712:Chlorides; D012997:Solvents; D014867:Water; D002586:Cesium; D058428:Silica Gel; D012822:Silicon Dioxide; C028019:cesium chloride; D005947:Glucose