C6–H Bond Functionalization of Indoles: A New Gate

Indoles are valuable precursors in medicinal, bioorganic, and material chemistry and particularly serve as a platform for diversity. However, the scope of the C6-functionalization of indoles was limited until recently. In this short review, we summarize developments in the C6-functionalization reactions of indoles involving transition-metal-cat-alyzed functionalization and Brunsted and Lewis acid catalyzed process -es. The regioselectivity is controlled by remote-C-H activation and hy-drogen bond formation. 1 Introduction 2 Transition-Metal-Catalyzed Functionalization 3 Acid-Catalyzed Processes 4 Conclusion