Radical Catalysis of Kumada Cross-Coupling Reactions Using Functionalized Grignard Reagents

Angew. Chemie Int. Ed., 2009, 48, 205-209 published on 03.12.2008
Angew. Chemie Int. EdAngew. Chemie Int. Ed.
The Kumada cross-coupling allows direct Pd-catalyzed carbon–carbon bond formation between unsaturated halides and organomagnesium reagents (without further transmetalation steps)[1, 2] and is therefore a highly atom-economical cross-coupling reaction.[3] Most of these cross-couplings follow a standard mechanism (oxidative addition, ligand exchange, reductive elimination),[4] although an alternative pathway is possible, as was shown by Kambe et al. for Kumada cross-couplings in the presence of dienes.[5] Recently, Buchwald and co-workers have shown that when an appropriate phosphine ligand[6] and low temperatures are used, functionalized aryl and heteroaryl iodides undergo a smooth cross-coupling with functionalized arylmagnesium halides.[7,8]
TU München