Abstract
This report highlights the recent advances in direct C–H bond functionalization of
5,5- and 6,5-fused heterocycles containing at least two nitrogen atoms. Besides C–C
bond formation, C–N, C–S, C–P, and C–Si bonds can also be created via a metal-catalyzed
process. Some examples, where a C–H functionalization approach was applied for the
synthesis of drug candidates, will be presented as well.
1 Introduction
2 C–H Functionalization Reactions of N-Containing Heterocycles
2.1 Imidazo[1,2-a]pyridines
2.2 Pyrrolo[1,2-a]pyrazines
2.3 Imidazo[1,2-b]pyrazoles
2.4 Imidazo[1,2-a]pyrimidines
2.5 Imidazo[1,2-a]pyrazines and Imidazo[1,5-a]pyrazines
2.6 Imidazo[1,2-b]pyridazines
2.7 Imidazo[4,5-b]pyridines and Imidazo[4,5-c]pyridines
2.8 Pyrazolo[3,4-b]pyridines
2.9 Pyrazolo[1,5-a]pyrimidines
2.10 Pyrrolo[2,3-d]pyrimidines and Pyrrolo[3,2-d]pyrimidines
2.11 Imidazo[1,2-b][1,2,4]triazines
2.12 Imidazo[1,2-b][1,2,4,5]tetrazines
3 Outlook
4 Conclusion
Key words
heterocycles - nitrogen - C–H bond - direct functionalization - catalysis - regioselectivity
