Metalated Indoles, Indazoles, Benzimidazoles, and Azaindoles and Their Synthetic Applications

Dedicated to Victor Snieckus on the occasion of his 76^th birthday

Abstract

This review focuses on the regioselective metalation of condensed azoles, such as indole, indazole, benzimidazole, 4-, 5-, 6-, and 7-azaindole. The metalation strategies discussed include halogen–metal exchange, metal insertion into carbon–halogen bonds, and directed deprotonation. The influence of different nitrogen-protecting­ groups and directed metalating groups is discussed. This review covers literature published mainly from 1991 to 2010.

1 Introduction

2 Metalation of Indoles

2.1 C2-Metalation of Indoles

2.2 C3-Metalation of Indoles

2.3 C4–C7-Metalation of Indoles

3 Metalation of Indazoles

4 Metalation of Benzimidazoles

5 Metalation of Azaindoles

6 Conclusion

Key words

metalation - indoles - heterocycles - cross-coupling - natural products

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