Recent Advances in KF/alumina Promoted Organic Reactions

Basudeb      Basu; Pralay      Das; Sajal      Das

doi:10.2174/138527208783330046

Abstract

Organic reactions promoted on a solid heterogeneous phase attract widespread interest within synthetic chemists from industries and academia. Potassium fluoride impregnated over aluminum oxide (KF/alumina) has been recognized as remarkably useful heterogeneous surface to promote many base-catalyzed organic transformations. The basic sites on KF/alumina may be associated to a very hard anion (F- anion), which possibly augments the surface to be active as a potential base and differentiates from other alkaline earth metal oxides as base catalysts. The source of the basicity has, however, been the subject of some debate in the literature. Besides classical organic reactions, such as alkylation, condensation and elimination reactions, KF/alumina has been successfully utilized as heterogeneous basic surface in several metal – catalyzed coupling reactions. Palladium-catalyzed C-C bond-forming reactions (e.g. Heck, Stille, Suzuki, Trost – Tsuji reactions), C-N bond-forming Buchwald-Hartwig reactions, and C-O bond-forming Baylis-Hillman type reactions have been reported with the aid of KF/alumina as the heterogeneous base. The KF/alumina catalyzed reactions are in many cases carried out without using any solvent, thus providing a clean and “green” reaction set up followed by easy product isolation. The solid surface has also been employed for preparing combinatorial libraries of different small molecules. In many cases, application of microwave irradiation has shown dramatic acceleration of the rate of transformations. This article will review the applications of KF/alumina in various organic reactions focusing on achievements during the period from 2001 to 2005.

Keywords: Aldol Condensation, Michael addition, Vesidryl synthesis, aminopyrimidine, Arylation

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