Vol.:(0123456789) 1 3 Catal Lett DOI 10.1007/s10562-017-2163-9 Pd/AlO(OH): A Heterogeneous, Stable and Recyclable Catalyst for N-Arylation of Aniline Under Ligand-Free Aerobic Condition Sundaram Ganesh Babu 1,2  · Balakumar Emayavaramban 1  · Peter Jerome 1  · Ramasamy Karvembu 1   Received: 14 March 2017 / Accepted: 2 August 2017 © Springer Science+Business Media, LLC 2017 Graphical Abstract Keywords Pd/AlO(OH) · Buchwald–Hartwig coupling · Ligand-free · Reusable · Heterogeneous · Aerobic condition 1 Introduction Amines are ubiquitous in biology. Many neurotransmitters are amines, including epinephrine, norepinephrine, dopa- mine, serotonin and histamine. Many amine-based drugs are designed to mimic or to interfere with the action of natural amine neurotransmitters. Ephedrine and phenylephrine, as amine hydrochlorides, are used as decongestants. Due to their interesting physiological activities, secondary amines are extremely important pharmacophores in numerous bio- logically active compounds, which have greatly been touted in drug discovery where the secondary amine can be utilized as important scafolding for further manipulations [1]. Sec- ondary amines are also a vital class of intermediates in the preparation of natural products. With the growing repertoire Abstract Many synthetic methods have been reported to construct an aryl-nitrogen bond. But they mainly sufer from the usage of expensive ligands. Herein, we report highly efective, heterogeneous, reusable and ligand-free nanocata- lyst for the Buchwald-Hartwig coupling reaction under aero- bic condition. Wafer-like structure with nano-porous nature of AlO(OH) was identifed with TEM and BET surface area analyses. Zero valent Pd nanoparticles (with less than 10 nm crystallite size which strongly evident from TEM analysis) were observed in XRD pattern, which was further confrmed by XPS studies. The reaction conditions were optimized and the scope of the reaction was extended with various aryl halides and aniline using low amount of Pd (0.31 mol%) based heterogeneous catalyst. Heterogeneity, reusability and stability (confrmed by XRD) were found to be reasonable. Use of meagre amount of Pd and the ligand-free aerobic condition make this system economically as well as envi- ronmentally feasible. * Sundaram Ganesh Babu Sundaram.Babu@uct.ac.za * Ramasamy Karvembu kar@nitt.edu 1 Department of Chemistry, National Institute of Technology, Tiruchirappalli 620015, India 2 Catalysis Institute, Department of Chemical Engineering, University of Cape Town, Cape Town 7701, South Africa