PEG-embedded potassium tribromide ([K+PEG]Br3-) 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 β-keto ester. At the end of the reaction the [K+PEG]Br3- was readily regenerated from the reaction mixture by treating the residue containing [K +PEG]Br3- with molecular bromine. © 2011 Verma et al; licensee Beilstein-Institut.
Verma, S., Jain, S. L., & Sain, B. (2011). PEG-embedded KBr3: A recyclable catalyst for multicomponent coupling reaction for the efficient synthesis of functionalized piperidines. Beilstein Journal of Organic Chemistry, 7, 1334–1341. https://doi.org/10.3762/bjoc.7.157