The application of inexpensive, non-toxic, commercially available, and environmentally benign iron complexes as catalysts in chemical syntheses has attracted much attention.

Wei Liu, Hao Cao, and Aiwen Lei, Wuhan University and Chinese Academy of Sciences, have successfully developed the first novel Fe-catalyzed direct arylation of unactivated arenes with a broad range of aryl halides, including aryl chlorides, bromides, and iodides, through C–H bond activation to prepare biaryl compounds. The reactions were carried out at relatively low temperature in the presence of a catalytic amount of FeCl₃, with DMEDA as the ligand and LiHMDS as the base (see scheme; DMEDA = N,N’-dimethylethane-1,2-diamine, HDMS = hexamethyldisilazanide). The choice of the base and ligand are essential to the success of this Fe-catalyzed direct arylation of unactivated arenes.

Further studies on the mechanism are actively underway.

• Iron-Catalyzed Direct Arylation of Unactivated Arenes with Aryl Halides,
  Wei Liu, Hao Cao, Aiwen Lei,
  Angew. .Chem Int. Ed. 2010, 49, 2004–2008.
  DOI: 10.1002/anie.200906870