Cu−NHC Complex for Chan‐Evans‐Lam Cross‐Coupling Reactions of N‐Heterocyclic Compounds and Arylboronic Acids

An efficient copper(II) N‐heterocyclic carbene (NHC) complex with an NCN coordination mode was optimized to catalyze the Chan–Evans‐Lam (CEL) cross‐coupling reaction of imidazole and other N‐heterocyclic nucleophiles with arylboronic acid. This air‐stable copper catalyst shows robust catalytic performance and tolerates a diverse array of functional groups on both the N‐nucleophile and arylboronic acid coupling partners in C−N bond forming reactions with up to 95 % yield. Formation of the Cu−NHC complex in situ generated similar catalytic performance for CEL coupling. Alternative metal ions (Mn2+, Fe2+, Co2+, Ni2+, Zn2+, Ru2+, and Pd2+) were also screened in the presence of the NHC precursor as CEL catalysts. An efficient copper(II) N‐heterocyclic carbene (NHC) complex catalyzing the Chan–Evans‐Lam cross‐coupling reaction of N‐heterocyclic nucleophiles with arylboronic acid has been explored. This air‐stable copper catalyst shows practical robustness that tolerates a diverse array of functional groups on both the N‐nucleophile and arylboronic acid coupling partners in C−N bond forming reactions through the CEL reaction.