Silica supported Fe(HSO4)3 as an efficient, heterogeneous and recyclable catalyst for synthesis of β-enaminones and β-enamino esters

A series of β-substituted enaminones were prepared through the one-pot reaction of β-dicarbonyl compounds with various amines in the presence of silica ferric hydrogensulfate under solvent free conditions at room temperature. The reactions proceed smoothly in excellent yield, high chemoselectivity and with an easy work-up. Catalytic amount of Fe(HSO4)3·SiO2 catalyzed one-pot reaction of linear and cyclic β-diketones and β-keto esters with aromatic and aliphatic amines. The B3LYP/6-31G** full optimizations were carried out for enol-enamine tautomers of enaminones.

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► A series of β-substituted enaminones were prepared and their stable tautomers were characterized.
► One-pot fast reaction of linear and cyclic β-diketones and β-keto esters with various amines was carried out.
► Silica ferric hydrogensulfate catalyze this reaction under solvent free conditions at room temperature.
► The reactions proceed smoothly in excellent yield and high chemoselectivity.
► The B3LYP/6-31G** full optimizations were carried out for enol forms of enaminones.