Switchable Regiodivergent Reductive Alkyl-Alkyl Coupling by Nickel Catalysis: Sorting Different Alkyl-Nickel Intermediates

Site-selective and divergent functionalizations on saturated alkyl chain at specific unfunctionalized positions is a key challenge in organic chemistry and other related areas and offers unprecedented synthetic opportunities. Herein, a ligand-controlled Ni-catalyzed site-selective and divergent alkyl-alkyl reductive coupling between two different alkyl halides has been developed. Notably, the reaction finely tunes and recognizes thermodynamic favored α-aminoalkyl radicals over β-aminoalkyl radicals, and distal ipso-alkyl radicals to deliver chemo- and position-selective alkylation of unactivated α-H and β-H of amines under reductive conditions. Moreover, the reaction selectively functionalizes one alkyl chain over two migratable alkyl chains. By just switching the catalytic parameters, α- and β-alkylation of saturated C─H bonds, and ipso-alkyl-alkyl coupling allow for rapid access to three types of branched aliphatic amine architectures from identical starting materials.