Fe₂O₃ Nano‐Catalyst Mediated Oxidative Decarboxylation CH Acylation/Benzoylation of 3‐Alkylidene‐2‐Oxindoles With α‐Keto Acids

Abstract

We successfully employed an environmentally friendly synthesized heterogeneous Fe2O3 nano‐catalyst‐mediated one pot approach to β CH bond acylation of 3‐Alkylidene‐2‐Oxindoles via oxidative decarboxylation of α‐keto acids. This method enabled the activation of Csp2‐H bonds, resulting in the formation of Csp2‐Csp2 single bonds and the generation of highly substituted derivatives of (E)‐2‐(2‐oxoindolin‐3‐ylidene)‐1‐aryl‐3‐substituted‐propane‐1,3‐diones and (E)‐3‐oxo‐2‐(2‐oxoindolin‐3‐ylidene)‐3‐substituted‐propanoates. The synthesized non‐toxic Fe2O3 nano‐material was meticulously characterized through FT‐IR, powdered XRD, HRTEM, EDX, BET, and ICP‐MS analyses. This heterogeneous catalyst can be conveniently recovered with a magnetic field and reused in subsequent reactions. This method offers excellent functional‐group tolerance, efficient substrate yield in less time, simple workup, and a recyclable catalyst.