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

We successfully employed an environmentally friendly synthesized heterogeneous Fe2O3 nano-catalyst-mediated one pot approach to beta C-H bond acylation of 3-Alkylidene-2-Oxindoles via oxidative decarboxylation of alpha-keto acids. This method enabled the activation of C-sp2-H bonds, resulting in the formation of C-sp2-C-sp2 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.