ChemInform Abstract: Chemistry of Monoorganopalladium Complexes Relevant to Catalysis

Abstract

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The First General and Selective Palladium(II)‐Catalyzed Alkoxycarbonylation of Arylboronates: Interplay among Benzoquinone‐Ligated Palladium(0) Complex, Organoboron, and Alcohol Solvent

“…[19] In either way, pbq-induced reductive elimination finally produces methyl benzoate and the pbq-ligated palladium(0) complex. It is likely that pbq acts as a p-acidic ligand toward palladium(II) acyl complexes 29 and 30 to facilitate reductive elimination by depriving the palladium(II) center of electron density.…”

Homogeneous Hydrogenation of Aldehydes, Ketones, Imines and Carboxylic Acid Derivatives: Chemoselectivity and Catalytic Activity

“…The reaction proceeds by oxidative addition of the anhydride followed by hydrogenolysis, and proceeds well in THF at 80 8C (*100 turnovers, unoptimized). However, aldehyde productivity is limited to 50% by the reaction mechanism that involves hydrogenolysis of Pd-acyl and Pdcarboxylato groups in [Pd(PPh 3 ) 2 (C(O)R)(O 2 CR)] to give an equal mixture of aldehydes and acids [105]. Very bulky anhydrides were significantly more difficult to reduce, which led this group to design a process for converting carboxylic acids into aldehydes in the presence of bulky anhydrides [105][106][107].…”

“…However, aldehyde productivity is limited to 50% by the reaction mechanism that involves hydrogenolysis of Pd-acyl and Pdcarboxylato groups in [Pd(PPh 3 ) 2 (C(O)R)(O 2 CR)] to give an equal mixture of aldehydes and acids [105]. Very bulky anhydrides were significantly more difficult to reduce, which led this group to design a process for converting carboxylic acids into aldehydes in the presence of bulky anhydrides [105][106][107]. Thus, heating a wide range of less sterically demanding acids in the presence of The reaction tolerates ketone, chloride, internal C=C bonds, esters, nitriles, and ether functional groups.…”

Rate and Mechanism of the Oxidative Addition of Benzoic Anhydride to Palladium(0) Complexes in DMF

“…The benzoic anhydride concentration was varied in the range 0.01Ϫ0.4  and the plot of the corresponding k obs value versus the benzoic anhydride concentration gave a straight line (Figure 1b). The reaction order in benzoic anhydride is thus ϩ1 [Equation (8)]. This establishes that the mechanism of the oxidative addition of the benzoic anhydride to [Pd 0 (PPh 3 ) 4 ] [Equations (4Ϫ7)] is the same as that already established for aryl halides and triflates.…”

“…Due to the continuous release of PPh 3 in the fast equilibrium (5) during the course of the oxidative addition, the kinetic law is expressed in Equation The value of k obs was calculated from the slope of the regression line [Equation (8)]. The benzoic anhydride concentration was varied in the range 0.01Ϫ0.4  and the plot of the corresponding k obs value versus the benzoic anhydride concentration gave a straight line (Figure 1b).…”