Palladium-catalysed Suzuki{Miyaura cross-coupling with imidazolylidene ligandssubstituted by crowded resorcinarenyl and calixarenyl units

Abstract

TwoN-heterocyclic carbene (NHC) palladium complexes of formula [PdBr2(NHC)(pyridine)] in which thecarbenic ring is anked by sterically crowded cavitand substituents were prepared from appropriate imidazolium saltsbearing either two resorcinarene or a combination of resorcinarene and calixarene fragments. Both complexes displayedhigh stability and good activities in the cross-coupling of aryl bromides with phenyl boronic acid. One of the imidazoliumsalts was characterised by an X-ray diffraction study.