Metal-Free C(sp3)–H Amination of 2-Oxindoles in Water: Facile Synthesis of 3-Substituted 3-Aminooxindoles

A novel metal-free C(sp3)–H amination of 2-oxindoles with alkylamines to afford C–N coupling products under mild conditions has been exploited. A series of 3-substituted 2-oxindoles and primary/secondary amines substrates were found to be well tolerated, affording the corresponding 3-substituted 3-aminooxindoles in 43%–92% yields. This method uses the economical and environmentally friendly “I2–TBHP” system, and the mechanistic studies revealed that the procedure undergoes through a radical pathway.