Diels-Alder Reactions of Cyclopentadiene with Several Ferrocenyl- and η6-Phenyltricarbonylchromium Analogues of Chalcone. Catalytic Effect of SiO2

Abstract

The Diels-Alder reaction of cyclopentadiene with eight electron deficient dienophiles was studied. The reaction was performed at room temperature using silica gel as an inorganic support, without solvent. Only one of the two possible Diels-Alder adducts was isolated in moderate to good yield. The structure of products with endo-oriented electron-withdrawing group was proved by 1H NMR spectrum and in one case (9b) by X-ray analysis.