Enantioselective Synthesis of spiro[indoline‐3,4‐ pyrrolo [3,4‐b]pyridines] via Organocatalysed Three‐Component Cascade Reaction

Asymmetric synthesis of spiro[indoline‐3,4‐pyrrolo [3,4‐b]pyridines] derivatives was first developed through organocatalytic cascade Knoevenagel/Michael/cyclization reaction using a quinidine ‐derived squaramide. Under the optimized conditions, the three‐component reaction of isatins, cyanoacetates, and 3‐aminomaleimides yield the desired heterocycle‐fused spirooxindoles in good yields (78–91%) with 53‐99% enantiomer excess (ee). Notably, this reaction enabled a broad substrate scope under mild conditions, and provided a convenient method for enantioselective construction of diverse spirooxindoles combined with dihydropyridine and maleimide skeleton, which brought great potential to build new bioactive chemical entities.