Synthesis of 2-Oxindoles from Substituted Indoles by Hypervalent-Iodine Oxidation

A practical conversion of indoles into the corresponding 2-oxindoles is achieved efficiently using a hypervalent iodine reagent. This oxidation is amenable to different substituted indoles, and allows the synthesis of a wide range of synthetically valuable substituted 2-oxindoles in up to 90% yield. Furthermore, Ropinirole, a drug used to alleviate the symptoms of Parkinson's disease, was synthesized in three steps in an overall yield of 44% using this method.