Selectivity Control in the Palladium-catalyzed Cross-coupling of Alkyl Nucleophiles.

Site-selectivity remains a major challenge in metal-catalyzed C-H bond functionalization. Most existing strategies rely on the introduction of a directing group or on the intrinsic reactivity of the substrate. In this account article, we describe the development of an alternative strategy based on the migration of an organopalladium species along an alkyl chain, wherein the phosphine ligand controls the cross-coupling site. This concept was first implemented with lithium enolates, and then extended to α-zincated alkylamines obtained by directed lithiation and transmetalation. Both the direct and the migrative cross-couplings, which are controlled by simply switching the ligand, furnish synthetically useful organic intermediates.