C O M M U N I C A T I O N S
noted above shows that this step is rate-limiting. Reductive
elimination then takes place quickly before reversible protonation
occurs.
References
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Scheme 2. Proposed Mechanism with and without Iron Salt
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In summary, the results of the studies described above demon-
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preparation of pyrido[1,2-a]benzimidazoles by using direct in-
tramolecular aromatic C-H amination of N-aryl-2-aminopyridines,
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Acknowledgment. We are grateful for the support of this work
by a Start-up Grant from Guangzhou Institutes of Biomedicine and
Health (GIBH), National Science Foundation of China (21072190)
and a grant-in-aid for scientific research from the Chinese Academy
of Sciences Innovation Grant (KSCXI-YW-10). We thank Dr.
Fayang Qiu for valuable discussions.
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Supporting Information Available: Experimental and characteriza-
tion details. This material is available free of charge via the Internet at
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