Abstract

The development of iron complexes as catalysts in organic transformations is attractive for a number of reasons. Iron is one of the most abundant metals in the earth’s crust, it is cheaper than the rare metals, and its toxicity is low. As the cost of rare and precious metals will increase in the Future, the development of new synthetic strategies based on iron are critical. In this brief summary, we discuss two innovative iron-catalysed C-C bond forming reactions through radicals, generated by redox chemistry, or by photocatalysis. These works shine light on the possibility to promote radical transformations by iron complexes that can be advantageously used as starting point to develop new methodologies for the formation of C-C bonds with a cheap and environmental friendly approach.

INTRODUCTION
Due to the low cost, availability and low toxicity of iron, its chemistry is now under active re-investigation as demonstrated by the increasing number of publications in this field.(1) Since the price of coinage metals is increasing, and their availability will probably become problematic, the development of new iron promoted reactions deserves particular attention and could be a useful tool for setting up new transformations, particularly on industrial scale. Although the iron promoted cross-coupling reactions were developed before the discovery of palladium catalysts,(2) the difficulties to understand, optimize, and develop this chemistry, retarded their practical uses for almost 20 years. More recently, thanks to the high level of sophistication that organometallic chemistry, ligands design, and computational tools have now reached, the quite capricious iron promoted reactions started to be reinvestigated and iron salts and complexes have been successfully used as catalysts in many different transformations (1). In these transformations, cycles in which radicals are formed seem to play a decisive role. On the other hand, iron is a red ...