Oxidative Addition Step in Reactions Involving Palladium Activation of Carbon-Halogen and Carbon-Oxygen Bonds

Effect of macrokinetic factors on the ligand-free Heck reaction with non-activated bromoarenes

“…corroborated by several works [11][12][13][14][15][25][26][27]. Moreover, with an increase in ArBr concentration the reaction rate increases not so much as product yield, which is indicative of a longer catalyst life-time [15,27]. Besides, the reaction has been of the negative order kinetics in Pd [25,26] (the same conclusion can be made from experimental data presented in reference [11]).…”

“…However, there is experimental evidence for the positive influence of intensive agglomeration on catalytic activity. For example, the presence of a small amount of reducing agent in the reaction with aryl bromides is always accompanied with an increase in catalytic activity [15,27]. High TOF obtained in our work (Fig.…”

“…a autocatalytic reaction [19]; b using PdCl 2 as a precursor process includes the stage of its previous dissolution; c more than second order kinetics in Pd(0) concentration [18]. corroborated by several works [11][12][13][14][15][25][26][27]. Moreover, with an increase in ArBr concentration the reaction rate increases not so much as product yield, which is indicative of a longer catalyst life-time [15,27].…”

“…The most active catalytic system including available PdCl 2 as a precatalyst, sodium formate as a reductant and arylbromide excess is the subject of this research [15,27].…”

Interplays between Reactions within and without the Catalytic Cycle of the Heck Reaction as a Clue to the Optimization of the Synthetic Protocol

“…Surely, employment of another catalyst precursor or base (for example, any acetate) will change the composition of formed complexes and their ratio at different periods of reaction. 32 Interestingly, using benzoic acid anhydride as an arylating agent, the expected Pd complexes with benzoate counterion corresponding to traditional mechanism are not detected during reaction with styrene. 33 The existence of such complexes, most likely, is possible only in halide-and acetate-free systems when a Pd(0) complex is employed as a catalyst precursor.…”