PEG-embedded KBr3: A recyclable catalyst for multicomponent coupling reaction for the efficient synthesis of functionalized piperidines

PEG-embedded potassium tribromide ([K(+)PEG]Br-3(-)) was found to be an efficient and recyclable catalyst for the synthesis of functionalized piperidines in high yields in a one step, three component coupling between aldehyde, amine and beta-keto ester. At the end of the reaction the [K(+)PEG]Br-3(-) was readily regenerated from the reaction mixture by treating the residue containing [K(+)PEG]Br- with molecular bromine.