Iron-Catalyzed Synthesis of Nitrogen-Containing Heterocycles

Iron-Catalyzed Synthesis of Nitrogen-Containing Heterocycles 

Functionalization of an unactivated C(sp )-H bond is one of the biggest challenges for chemists and continues to attract the attention of the synthetic 

3-arylquinolines were obtained in 50-82% yields. It was noted that this is an inexpensive and convenient approach to 3-arylquinolines from simple and readily available starting materials and reagents. 

In 2010, Zhu and coworkers first reported the direct intramolecular C(sp )-H amination of Af-arylpyridine-2-ammes using a combination of Cu(OAc)2 and Fe(N03)3 as a bimetalUc catalytic system to furnish pyrido[l,2-a]benzimidazoles in satisfactory yields [13]. The authors believe that a Cu(lll)-catalyzed electrophilic aromatic substitution (SEAr) pathway is operating in this process according to the results of mechanistic studies, wherein iron(lll) acts a unique role to facilitate the formation of the more electrophilic Cu(III) species because in the absence of iron(III), a much less efficient and reversible Cu(II)-mediated SEAr process takes place. 

The iron-catalyzed direct intramolecular C(sp )-H amination of 2-benzhydrylpyridines for the synthesis of pyrido[l,2- ]indoles has also been 

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