Copper-Promoted Tandem Radical Reaction of 2-Oxindoles with Formamides: Facile Synthesis of Unsymmetrical Urea Derivatives

摘要

A convenient copper-promoted tandem radical reaction of 2-oxindoles with formamides producing unsymmetrical urea derivatives is described. This radical-mediated reaction enables the formation of one C=O and one C-N bond through a domino C-O coupling, ring cleavage and C-N coupling process, which features a broad substrate scope and excellent selectivity. In addition, tBuOOH not only acts as the oxidant, but also as the oxygen source. The proposed reaction mechanism is supported by control experiments.