Diastereoselective Synthesis of 3-(Aminoalkylidene)oxindoles via a Nucleophilic Vinylic Substitution of 2-Chloropyridinium Salts

A novel, mild, and diastereoselective method has been reported for the synthesis of 3-(aminoalkylidene)oxindoles via a sequential condensation-hydrolysis- nucleophilic vinylic substitution reaction of 2-chloropyridinium salts, isatins, and amines in ethanol at room temperature. The reaction proceeds under mild reaction conditions, offering good yields and diastereoselectivity in a short reaction time using commercially available starting materials, while exhibiting excellent tolerance for diverse functional groups.