Abstract

Abundant, inexpensive, and nontoxic iron salts can efficiently catalyze the cross-coupling reaction of organic electrophiles with organometallic reagents. A large variety of aryl, acyl, alkenyl, allylic, benzylic, propargylic, and alkyl electrophiles can be successfully coupled with organomagnesium, -zinc, -copper, -manganese, and -boron reagents. Coupling reactions of two organometallic reagents under oxidative conditions and of two organic halides under reductive conditions are also discussed. The reaction mechanism is controversial and various mechanisms, sometimes interconnected, in which iron can adopt different oxidation states have been proposed. Electron-transfer processes may also be involved.