CH Functionalization/CN Bond Formation: Copper‐Catalyzed Synthesis of Benzimidazoles from Amidines

Copper closes the ring: Benzimidazoles are synthesized from amidines through a copper-catalyzed CH functionalization/CN bond-forming process. The method tolerates a broad range of functional groups and provides the benzimidazoles in up to 89 % yield. Best results are obtained by using 15 mol % Cu (OAc) 2, 2–5 equivalents of HOAc as additive, and oxygen as the stoichiometric reoxidant (see scheme). Supporting information for this article is available on the WWW under http: //www. wiley-vch. de/contents/jc₂002/2008/z705420ₛ. pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.