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.