CHAPTER 4: Iron-Catalyzed Cross-Dehydrogenative-Coupling Reactions

In transition metal catalyzed cross-dehydrogenative-coupling (CDC) reactions for the efficient building of C–C bonds from two C–H bonds, iron is an inexpensive and earth abundant metal that has attracted increasing interest during the last few years. Using commercially available iron salts (such as FeCl₃, FeCl₂, Fe(OAc)₂), or organometallic precursors (such as Fe₂(CO)₉) as catalysts, in the presence of stoichiometric amounts of oxidants such as tert-butyl hydroperoxide, di-tert-butyl peroxide, DDQ, TEMPO oxoammonium salts, or even oxygen, sp³– sp³, sp³–sp², sp³–sp and sp²–sp² C–C bond formation can be efficiently performed. This is a breakthrough in terms of greener chemistry! Interestingly, this iron-catalyzed methodology also allows more sophisticated heterocyclic and/or polycyclic compounds to be prepared in tandem sequences.