PEPPSI-Type Palladium–NHC Complexes: Synthesis, Characterization, and Catalytic Activity in the Direct C5-Arylation of 2-Substituted Thiophene Derivatives with Aryl Halides

M. Kaloğlu (1) , I. Özdemir (1) , V. Dorcet (2) , Christian Bruneau (2) , H. Doucet (2)

1 Inönü University
2 ISCR - Institut des Sciences Chimiques de Rennes

Six benzimidazolium salts, having two nitrogen atoms substituted by various alkyl groups, have been synthesized in high yields. The benzimidazolium salts readily converted into the corresponding PEPPSI-type palladium–NHC complexes (PEPPSI = pyridine-enhanced precatalyst preparation, stabilization, and initiation). The structures of all compounds have been characterized by 1H NMR, 13C NMR, and IR spectroscopy, as well as elemental analysis techniques, which support the proposed structures. The molecular structure of one complex has been determined by single-crystal X-ray diffraction. The catalytic activity of the PEPPSI-type palladium–NHC complexes has been evaluated with respect to the direct C5-arylation of 2-substituted thiophene derivatives with various aryl halides. This arylation occurs efficiently and selectively at the C5-position of 2-substituted thiophene derivatives.

Keywords: Palladium; Substituted thiophenes; Heterocycles; Benzimidazolium salts; Carbenes

Domains: Chemical Sciences; Catalysis; Chemical Sciences; Organic chemistry

M. Kaloğlu, I. Özdemir, V. Dorcet, Christian Bruneau, H. Doucet. PEPPSI-Type Palladium–NHC Complexes: Synthesis, Characterization, and Catalytic Activity in the Direct C5-Arylation of 2-Substituted Thiophene Derivatives with Aryl Halides. European Journal of Inorganic Chemistry, 2017, 2017 (10), pp.1382-1391. ⟨10.1002/ejic.201601452⟩. ⟨hal-01515148⟩