Bartoli Giuseppe, Fernandez-Bolaños José G, Di Antonio Giustino, Foglia Gioia, Giuli Sandra, Gunnella Roberto, Mancinelli Michele, Marcantoni Enrico, Paoletti Melissa
Dipartimento di Scienze Chimiche, Università di Camerino, via S. Agostino 1, I-62032 Camerino (MC), Italy.
J Org Chem. 2007 Aug 3;72(16):6029-36. doi: 10.1021/jo070384c. Epub 2007 Jul 13.
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.
醛糖与β-二羰基化合物的克诺文纳格尔缩合反应生成具有多羟基烷基化烷基侧链的呋喃衍生物；该反应被称为加西亚·冈萨雷斯反应。尽管这些多羟基烷基呋喃是合成化学家在合成各种具有生物学意义的分子时可利用的有趣骨架，但所报道的方法存在条件苛刻的问题。开发一种通用且更高效的方案具有相当重要的意义，在本手稿中，我们希望探索碘化钠在增强CeCl₃·7H₂O作为加西亚·冈萨雷斯反应中有用的耐水路易斯酸促进剂活性方面的作用。使用我们负载在SiO₂上的体系，该反应在50℃无溶剂条件下以良好的产率进行，并且代表了一种制备密集官能化分子的简单便捷方法。此外，关于碘化物在我们这种多相反应中的作用的首次机理研究定性结果，可能对优化现有有机转化反应以及开发新的反应具有价值。
