Carbon–Carbon Bond Formation by Asymmetric Iron- and Cobalt-Catalyzed Reactions

The carbon–carbon bond formation is one of the most important chemical transformations for the construction of organic molecules. To accomplish this in an enantioselective manner, significant progress has been made in recent decades using precious 4d transition metals as catalysts. However, more recently, the use of earth-abundant transition metals has received increasing attention due to their abundant natural occurrence, affordable cost, and environmental compatibility. In particular, catalysis with earth-abundant cobalt and iron for enantioselective carbon–carbon bond-forming reactions has attracted significant interest. Indeed, more and more reaction types are disclosed in this research field, with a variety of enantioselective reactions such as oxidative coupling reactions, cross-coupling reactions, nucleophilic additions, cyclizations, hydrofunctionalization reactions, radical reactions, cyclization reactions, and C–H activation reactions already being described. In line with this trend, it can be anticipated that in the near future this strategy will also gain further relevance in industrial applications for the synthesis of, for example, optically pure pharmaceuticals and agrochemicals. In this chapter, we summarize the key developments in carbon–carbon bond formation by asymmetric cobalt- and iron-catalyzed reactions, highlighting aspects such as ligand design and mechanistic studies as well as synthetic applications.