Ruthenium(II) Acetate Catalyst for Direct Functionalisation of sp2-C-H Bonds with Aryl Chlorides and Access to Tris-Heterocyclic Molecules

The in situ generated (p-cymene)ruthenium diacetate [Ru(OAc)(2)(P-cymene)] catalyst 2, prepared from the (p-cymene)ruthenium dichloride dimer {[RuCl2(p-cymene)](2), 1} and potassium acetate (KOAc), acts as an excellent catalyst for ortho C-H bond functionalisation of 2-pyridylbenzene with unactivated aryl chlorides in the presence of potassium carbonate (K2CO3). Quantitative diarylation can be reached in 1 h at 120 degrees C. The diarylation of 2-pyridylbenzene with 2-halopyridines and 2- and 3-halothiophenes was performed with 1 in the presence of KOAc or K2CO3 under more drastic conditions to generate the potential tridentate ligands, tris[1,2,3-(2-pyridyl)]benzenes and bis(2,6-thioplienyl)2-pyridylbenzenes.