3.07 Coupling Reactions Between sp 3 -Carbon Centers

The formation of carbon–carbon bonds between sp 3 -carbons, catalyzed by transition metals, remains much less developed in comparison with the well-recognized cross-coupling reactions between unsaturated sp - and sp 2 -carbons until approximately a decade ago. A remarkable evolution in this field happened at the beginning of this century which was triggered by employing new ligands, including bulky alkylphosphines, di- or tri-amines, π-carbon ligands, and N -heterocyclic carbenes. These reactions can be catalyzed by Fe, Co, Ni, Pd, Cu, and Ag and constitute powerful tools in the area of synthetic chemistry for constructing carbon chains as the fundamental frameworks of organic molecules. This chapter focuses on the rapid growth of new techniques for connecting sp 3 -carbon centers, including stoichiometric and catalytic cross-coupling reactions of unactivated alkyl (pseudo)halides with various alkylmetals as well as reactions involving allylic and benzylic carbons. The homocoupling of alkyl halides promoted by reducing reagents and that of alkylmetals using oxidizing reagents is also discussed.