Abstract
Mixed NHC–Pd–PPh3 complexes with a methoxyethyl-substituted N-heterocyclic carbene (NHC) were synthesised and characterised by NMR, HRMS, elemental analysis and X-ray crystallography for complex 3b. These complexes were applied to Sonogashira cross-coupling reactions between aryl bromides and phenylacetylene in DMF at 80 °C. All palladium complexes were stable and showed high catalytic activity in Sonogashira reactions at low catalyst loading and ambient reaction conditions.
NHC-Pd-PPh3 complexes used as catalyst for the Sonogashira coupling reaction and they exhibited high catalytic activities with bromo substrates. [Display omitted]
•A series of benzimidazole based N-heterocyclic carbene precursors and their Pd-PEPPSI and Pd-PPh3 complexes were synthesized and characterized.•NHC-Pd-PPh3 complexes used as catalyst for the Sonogashira coupling reaction.•They exhibited high catalytic activities for Sonogashira coupling of bromo substrates.