A Homolytic Substitution Approach for Directing Group-Free Nickel-Catalyzed Dialkylation of Unactivated Alkenes

The selective construction of two C(sp3)–C(sp3) bonds through trimolecular cross-coupling of unactivated alkenes remains one of the most difficult challenges in organic synthesis. Despite previous advances in metal-catalyzed coupling for the dicarbofunctionalization of alkenes, dialkylation is still problematic due to the instability of the requisite metal–alkyl intermediate, which undergoes facile β-hydride elimination or protodemetalation. Recently, our group was successful in developing a bimolecular homolytic substitution (SH2) strategy that circumvents metal–alkyl side reactions and accomplishes the challenging cross-coupling of metal–alkyl intermediates with alkyl radicals in the absence of a directing auxiliary, permitting a highly regioselective dialkylation of unactivated alkenes. 1 Introduction 2 Nickel-Catalyzed Dicarbofunctionalization of Unactivated Alkenes 3 Nickel-Catalyzed Dialkylation of Unactivated Alkenes 4 Conclusions and Perspectives