NHC as a Ligand in Heterobimetallic Catalysis: An Insight into a Catalytic Friedel–Crafts-like Reaction

The calculation of local reactivity descriptors, namely, local electron density and the Fukui function index for nucleophilic attack at a center, established that in transition metal–tin heterobimetallic complexes, N-heterocyclic carbene (NHC) is a better ligand than its alkene and phosphine analogues for the coupling of C–H and C–OH bonds. This insight was verified by synthesizing a new complex (NHC)₂Pd(Br)(SnCl₃), which turned out to be an excellent catalyst for the coupling of arene/heteroarene with alcohol (0.5–1 mol %; 60 °C; >35 examples; high TOF). Results from kinetic and thermodynamic studies have been described. Correspondingly, a mechanism is proposed.