ABSTRACT Sonogashira reaction involving the coupling of aryl halides with terminal alkynes is usually carried out with a palladium catalyst in combination with a copper co‐catalyst. Though this reaction has widely emerged as a cornerstone method for constructing C(sp 2 )─C(sp) bonds, efforts are continuing to replace the expensive catalysts with non‐precious metals in search for more green, sustainable, and cost‐effective catalytic systems. In this regard, we hereby report the development of an immobilized iron complex as an efficient, reusable heterogeneous catalyst for Sonogashira reaction under copper/ligand‐free conditions. This complex ( mPAN‐Fe ) was easily prepared by immobilizing the metal salt with functionalized polyacrylonitrile (PAN) and was characterized using Fourier Transform Infrared Spectroscopy (FTIR), x‐ray Diffraction (XRD), Energy Dispersive x‐ray Analysis (EDAX), Inductively Coupled Plasma–Mass Spectrometry (ICP‐MS), x‐ray Photoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), UV–Vis diffuse reflectance spectra (DRS) and computational analyses. Subsequently, mPAN‐Fe was optimized as an efficient catalyst for promoting Sonogashira coupling between a series of aryl halides and phenyl acetylenes to afford the corresponding products up to 84% yields. Moreover, the catalyst offered excellent reusability by retaining its catalytic activity up to five successive reaction cycles.
Shajahan et al. (Sun,) studied this question.