Synergistic Ni/Co catalysis in C(sp2)–C(sp3) reductive coupling: a DFT study

Abstract

In nickel-catalyzed C(sp²)–C(sp³) cross-coupling, employing cost-effective cobalt complexes as co-catalysts presents distinct advantages. The Ni/Co dual-catalyzed reductive coupling of aryl halides and alkyls has emerged as a powerful strategy to form C(sp²)–C(sp³) bonds, yet its detailed mechanistic understanding remains elusive. Herein, we elucidate the mechanism for the reductive coupling between aryl and alkyl electrophiles in the presence of a Ni/Co^II(PC) dual catalytic system by density functional theory (DFT). The cobalt catalyst activates alkyl halides via an S_N2 oxidative addition pathway, generating a Co^III(Pc)-Alk intermediate, while the nickel catalyst specifically engages aryl halides. The subsequent anti-alkylation step between these intermediates drives the formation of C(sp²)–C(sp³) bonds with high selectivity. These mechanistic insights not only rationalize the enhanced efficiency and high functional-group compatibility of the Ni/Co system but also provide a framework for developing future dual-metal catalytic methodologies. Our findings advance synthetic strategies for constructing complex molecules and highlight the potential of bimetallic catalysis in organic synthesis.