Oxidative Dearomatization of Indoles via Pd-Catalyzed C–H Oxygenation: An Entry to C2-Quaternary Indolin-3-ones

• Published in: Organic letters Vol. 18; no. 7; pp. 1534 - 1537
• Main Authors: Guchhait, Sankar K, Chaudhary, Vikas, Rana, Vijay A, Priyadarshani, Garima, Kandekar, Somnath, Kashyap, Maneesh
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01-04-2016
• ISSN: 1523-7060; 1523-7052
• DOI: 10.1021/acs.orglett.6b00244

An oxidative dearomatization chemistry of 2-arylindole via a unique pathway involving Pd-catalyzed C–H peroxygenation is documented. Coupled with cascade transformation, it provides a new route to access indolin-3-ones bearing a C2-quaternary functionality, including a chiral center (indoxyls), a motif prevalent in indole alkaloids but synthetically underexplored. The method is chemo- and regioselective and compatible with versatile substrates. A mechanism has been outlined on the basis of results of control experiments, isolation/use of intermediates, and spectroscopic studies.