Abstract
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-catalyzed
functionalization and Brønsted and Lewis acid catalyzed processes. The regioselectivity
is controlled by remote-C–H activation and hydrogen bond formation.
1 Introduction
2 Transition-Metal-Catalyzed Functionalization
3 Acid-Catalyzed Processes
4 Conclusion
Key words
indole - C–H bond activation - directing group (DG) - transition metal (TM) - acid
catalyst - hydrogen bond - electrophilic aromatic substitution (EAS)