Multicomponent preparation of highly functionalized piperidines using FeCl3.6H2O as an efficient catalyst

FeCl3.6H2O was used as an efficient catalyst for the synthesis of highly functionalized piperidines via a one-pot five-component reaction of aromatic amines, aromatic aldehydes and β-keto esters in EtOH at room temperature. The remarkable advantages offered by this method are good yields, simple procedure, short reaction times, no need to column chromatography and easy work-up. The structures of all compounds were characterized by comparison of their IR and NMR spectra with authentic samples. Also, the relative stereochemistry of these piperidines has been confirmed by single X-ray crystallography analysis in previously reported literature. Starting materials with electron-deficient or electron-releasing groups were reacted efficiently.