Palladium-catalysed Suzuki--Miyaura cross-coupling with imidazolylidene ligands substituted by crowded resorcinarenyl and calixarenyl units

Authors: NESLIHAN SAHIN, DAVID SEMERIL, ERIC BRENNER, DOMINIQUE MATT, CEMAL KAYA, LOIC TOUPET

Abstract: Two $N$-heterocyclic carbene (NHC) palladium complexes of formula [PdBr$_{2}$(NHC)(pyridine)] in which the carbenic ring is flanked by sterically crowded cavitand substituents were prepared from appropriate imidazolium salts bearing either two resorcinarene or a combination of resorcinarene and calixarene fragments. Both complexes displayed high stability and good activities in the cross-coupling of aryl bromides with phenyl boronic acid. One of the imidazolium salts was characterised by an X-ray diffraction study.

Keywords: Resorcinarene, calixarene, cavitands, $N$-heterocyclic carbene, palladium, PEPPSI complexes, Suzuki--Miyaura coupling

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