An efficient synthesis of functional stilbenes in Hiyama coupling reaction catalysed by H-spirophosphorane palladium complex

An efficient Hiyama cross-coupling reaction of functionalised styrylsilanes with iodo- and bromobenzene has been performed using complex [PdCl2P(OCH2CMe2NH) OCH2CMe2NH2] as precatalyst. The styrylsilanes underwent cross-coupling reactions with excellent selectivity and yield, up to 99%, of the corresponding E-stilbenes. When (E)-[1-(4-bromophenyl)-2-(1,1,3,3,3-pentamethyldisiloxy)]ethene was used as a source of the silane, a homocoupling reaction took place and polymeric compound containing 0.77% of palladium in the form of Pd(0) nanoparticles was obtained. This material used as a catalyst made it possible to obtain 40% and 38% of the Hiyama cross-coupling product in two subsequent runs.

Figure optionsDownload high-quality image (132 K)Download as PowerPoint slideHighlights
► Pd complex with H-spirophosphorane ligand as catalyst precursor.
► Remarkably active precatalyst for Hiyama cross-coupling reactions.
► Homo- and heterogenous precatalyst from the one molecular.
► Preparative method for stilbene receiving.