Microwave-Assisted One-Pot [3+2] Cycloaddition of Azomethine Ylides and 3-Alkenyl Oxindoles: A Facile Approach to Pyrrolidine-Fused Bis-Spirooxindoles

An efficient microwave-assisted one-pot method has been developed for the construction of pyrrolidine fused bis-spirooxindoles through insitu generated azomethine ylide from decarboxylative condensation of isatins and primary alpha-amino acids with concomitant [3+2] cycloaddition of 3-alkenyl oxindoles. These reactions were effectively accelerated by microwave irradiation in ethanol solvent without any additives or catalyst and enable broad substrate scope, atom-economy, eco-friendly, and good yields. The structure and stereochemistry of pyrrolidine fused bis-spirooxindole ring was unambiguously established by single-crystal X-ray analysis.