FeCl₃‐Catalyzed [3+2] Cycloaddition Reaction: A Mild Synthetic Approach to Spirooxindolo‐2‐iminothiazolidine Scaffolds

Abstract

A facile one‐pot [3+2] cycloaddition reaction for the synthesis of diversely substituted spirooxindolo‐2‐iminothiazolidine scaffolds has been accomplished by employing FeCl3 as catalyst. This reaction proceeds via Lewis acid‐mediated activation of spiro‐oxindole aziridines to generate a 1,3‐dipole which undergoes intramolecular cycloaddition with different aryl/alkyl isothiocyantes. The present method offers atom economy, broad substrate scope, good to moderate yields, and wide functional group tolerance. In addition, one of the representative structures was confirmed by single X‐ray crystallography analysis.

Transition metal-catalyzed synthesis of spirooxindoles

“…68 It was a novel catalyst made by the assembly of Au-Ag alloy NPs on the surface of A novel procedure for the synthesis of spirooxindolo-2iminothiazolines 96 catalyzed by FeCl 3 was established. 70 It involves a [3 + 2] cycloaddition reaction between aryl/alkyl isothiocyanates 94 and 1,3-dipoles produced from spirooxindole aziridines 95. The one-pot reaction proceeded with FeCl 3 (10 mol%) in dichloromethane at À20 C (Scheme 45).…”