A ruthenium complex prepared in situ from [RuCl2(p-cymene)]2 and TpMe2K [TpMe2 = hydrotris(3,5-dimethylpyrazolyl)borate] is efficient for aromatic C–H borylation with pinacolborane (4,4,5,5-tetramethyl-1,3,2-dioxaborolane). Arenes were borylated at more electron-rich positions. DFT calculations and kinetic isotope effect experiments suggest that the catalytic cycle should involve an electrophilic aromatic substitution with a borenium cation.
Abbreviations for hydrotris(pyrazolyl)borate ligands follow the accepted nomenclature. See: TrofimenkoS., Scorpionates: The Coordination Chemistry of Polypyrazolylborate Ligand, Imperial College Press, London, 1999.
8.
MurphyJ.M., LawrenceJ. D., KawamuraK., IncarvitoC., and HartwigJ. F., J. Am. Chem. Soc., 2006, 128, 13684.
9.
StahlT., MutherK., OhkiY., TatsumiK., and OestreichM., J. Am. Chem. Soc., 2013, 135, 10978.
10.
Fernández-SalasJ.A., ManziniS., PiolaL., SlawinA. M. Z., and NolanS. P., Chem. Commun., 2014, 50, 6782.
11.
OkadaS., NamikoshiT., WatanabeS., and MurataM., ChemCatChem, 2015, 7, 1531.
12.
OlahG.A., KuhnS. J., and FloodS. H., J. Am. Chem. Soc., 1961, 83, 4571.
13.
NakaneR., KuriharaO., and TakematsuA., J. Org. Chem., 1971, 36, 2753.
14.
AlcockN.W., BurnsI. D., ClaireK. S., and HillA. F., Inorg. Chem., 1992, 31, 2906.
15.
JalónF.A., OteroA., and RodríguezA., J. Chem. Soc., Dalton Trans., 1995, 1629.
