Sonogashira Cross-Coupling Reaction Catalysed by Mixed NHC-Pd Complexes Under Copper-Free Conditions

Abstract

Mixed NHC–Pd–PPh<inf>3</inf> 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. © 2018 Elsevier B.V.