Evidence for Suzuki-Miyaura cross-couplings catalyzed by ligated Pd-clusters: from cradle to grave.

Pd clusters offer unique selectivity and exploitable reactivity in catalysis. Understanding the behavior of Pd clusters is thus critical for catalysis, applied synthetic organic chemistry and greener outcomes for precious Pd. The Pd cluster, [Pd(μ-Cl)(μ-PPh)(PPh)][Cl] (denoted as PdCl), which exhibits distinctive reactivity, was synthesized and immobilized on a phosphine-functionalized polystyrene resin (denoted as immob-PdCl).

Opening a Pandora's Flask on a Prototype Catalytic Direct Arylation Reaction of Pentafluorobenzene: The AgCO/Pd(OAc)/PPh System.

Direct C-H functionalization reactions have opened new avenues in catalysis, removing the need for prefunctionalization of at least one of the substrates. Although C-H functionalization catalyzed by palladium complexes in the presence of a base is generally considered to proceed by the CMD/AMLA-6 mechanism, recent research has shown that silver(I) salts, frequently used as bases, can function as C-H bond activators instead of (or in addition to) palladium(II). In this study, we examine the coupling of pentafluorobenzene to 4-iodotoluene (and its analogues) to form 4-(pentafluorophenyl)toluene catalyzed by palladium(II) acetate with the commonplace PPh ligand, silver carbonate as base, and DMF as solvent.

Reactivity of a Dinuclear Pd Complex [Pd(μ-PPh)(μ-OAc)(PPh)] with PPh: Implications for Cross-Coupling Catalysis Using the Ubiquitous Pd(OAc)/nPPh Catalyst System.

[Pd (μ-PPh)(μ-OAc)(PPh)] is the reduction product of Pd(OAc)(PPh), generated by reaction of 'Pd(OAc)' with two equivalents of PPh. Here, we report that the reaction of [Pd (μ-PPh)(μ-OAc)(PPh)] with PPh results in a nuanced disproportionation reaction, forming [Pd(PPh)] and a phosphinito-bridged Pd-dinuclear complex, namely [Pd (μ-PPh){κ-P,O-μ-P(O)Ph}(κ-PPh)]. The latter complex is proposed to form by abstraction of an oxygen atom from an acetate ligand at Pd.

A Dichotomy in Cross-Coupling Site Selectivity in a Dihalogenated Heteroarene: Influence of Mononuclear Pd, Pd Clusters, and Pd Nanoparticles-the Case for Exploiting Pd Catalyst Speciation.

Site-selective dihalogenated heteroarene cross-coupling with organometallic reagents usually occurs at the halogen proximal to the heteroatom, enabled by intrinsic relative electrophilicity, particularly in strongly polarized systems. An archetypical example is the Suzuki-Miyaura cross-coupling (SMCC) of 2,4-dibromopyridine with organoboron species, which typically exhibit C2-arylation site-selectivity using mononuclear Pd (pre)catalysts. Given that Pd speciation, particularly aggregation, is known to lead to the formation of catalytically competent multinuclear Pd species, the influence of these species on cross-coupling site-selectivity remains largely unknown.