Waste-Minimized Continuous-Flow Synthesis of Oxindoles Exploiting a Polymer-Supported N Heterocyclic Palladium Carbene Complex in a CPME/Water Azeotrope

Herein, we report the development of an effective synthetic protocol for synthesis oxindoles in flow based on a C(sp3)–H activation process promoted by supported N-heterocyclic carbene palladium heterogeneous catalytic system using cyclopentyl methyl ether (CPME) as reaction medium. The design catalyst, selection solvent medium, and definition tailored continuous reactor have been all designed to establish efficient waste-minimized intramolecular cyclization N-methyl-2-halo-acetanilides. use CPME its aqueous azeotropic mixture has allowed us reach high yields products with simplified precipitation workup that includes downstream separation recycling solvent. An assessment environmental safety hazard features also made order better clarify implications terms sustainability newly developed process.