Palladium (II) complexes with the unsymmetrical H-spirophosphorane ligand HP(OCMe2CMe2O)(OCH2CMe2NH): Synthesis, structural and catalytic studies

Carbonylative Suzuki Coupling Reaction Catalyzed by a Hydrospirophosphorane Palladium Complex

“…Clearly, the long‐term use of the catalyst resulted in a change of its reactivity. In particular, the ability to activate CO and form diarylketone decreased . We assumed that the black residue used in this experiment contained mainly Pd NPs, however, the presence of some precipitated Pd complex is also possible.…”

“…These different bond lengths are caused by the stronger trans effect of the P atoms than the N atoms. The Pd−N n 1 bond lengths of 2.040(3) and 2.057(4) have a similar values to those in complexes that contain a chelate ( ) ligand and two Cl atoms …”

“…Pd complexes with HSPs have been applied as efficient and regioselective catalysts in Heck and Hiyama cross‐coupling reactions. It emerged that the presence of the spirophosphorane ligand in the coordination sphere of Pd is essential, and the structure of the complex plays a significant role in the catalytic process . It was demonstrated that the kind of HSP ligand coordinated to Pd influences the selectivity of the arylation of n ‐butyl acrylate and the yield of substituted stilbenes in the coupling reaction of aryl halides with substituted styrenes and styrylsilanes.…”

Nanocatalysts for Hiyama, Stille, Kumada, and Negishi C–C Coupling Reactions

“…96 Presence of an induction period during the course of the reaction, or drop in catalytic activity owing to poisoning by Hg, strengthened this argument; however, most of the earlier studies could, at best, identify the Pd-NPs formed, but not comment on their catalytic contributions. 97 One of the earliest examples of Pd-NPs playing a role in Hiyama coupling was published in 2007 by Shi and Zhang, where Pd(OAc) 2 -catalyzed fluoride-free crosscoupling between the aryl bromides and arylsiloxanes was studied in water containing the polymer PEG-200 under ambient conditions. 48 However, it was observed that the reaction was significantly less successful (74% yield of cross-coupled product in pure water as opposed to 92% in a 3 : 3 water/PEG-200 mixture) in the absence of the PEG nanoparticle-stabilizing agent.…”

“…Darkening of the reaction mixture after one catalytic cycle also indicated the formation of nanoparticles. 97 There are many studies in the recent literature on the Pd-NP intermediates as the active species in Hiyama coupling reactions. In 2009, Bauerlein et al devised an elegant synthesis of an electron-deficient alkene functionality (such as chalcone and benzylidene acetone) doped common ILs, which were shown to be very promising reaction media for Hiyama coupling in the presence of a Pd(OAc) 2 precatalyst.…”