Five new unsymmetrically substituted salts containing a benzimidazole backbone
were synthesized in high yields and their structures were verified via spectroscopic and analytical
methods such as HRMS, 1D and 2D NMR spectroscopy, FT-IR and elemental analysis.
The catalytic properties of all the synthesized salts were tested in a homogeneous Suzuki-Miyaura cross-coupling reaction to get coupling products in high efficiencies with low
amounts of in situ formed catalysts. In this reaction, the couplings of boronic acid derivatives
with different aryl chlorides were made in the presence of palladium acetate, 2-6 and base at
various times and temperatures. According to the obtained results, the benzimidazolium salts
which are N-heterocyclic carbene (NHC) ligand precursors were found to have high catalytic
activity. In particular, the coupling of 4-chlorotoluene with phenylboronic acid was obtained
in very high yield and conversion in the catalyzed Pd-NHC complexes which were in situ
formed from compounds 3 and 6 and Pd(OAc)2.