Highly Enantioselective Hydroxycarbonylation and Alkoxycarbonylation of Alkenes using Dipalladium Complexes as Precatalysts

Superphenylphosphines: Nanographene-Based Ligands That Control Coordination Geometry and Drive Supramolecular Assembly

“…Despite a P···P distance of 6.186(1) Å, anti- Pd 2 Cl 4 ( 1 ) 2 (Figure a) adopts a close inter-HBC contact (3.40 Å) which induces significant curvature across the interacting HBCs (up to 15.9° side-to-side) and a reduction of the Pd···Pd distance to 2.9294(4) Å. This is the shortest Pd···Pd distance reported for a bis-monodentate phosphine Pd 2 Cl 4 L 2 complex, with only a bidentate ligand complex showing greater distortion …”

“…30–33 ppm), consistent with mixtures of syn and anti isomers. With few exceptions, bis-monodentate phosphine Pd 2 Cl 4 L 2 complexes favor the anti configuration, presumably due to steric demand in the coordination sphere, while bidentate phosphines favor the syn isomer. − That monodentate ligands 1 – 3 all give isomeric mixtures indicates competing effects of the HBC substituents; intracomplex π–π interactions between HBC fragments act to stabilize the syn isomer, while the steric bulk has a destabilizing effect favoring the anti isomer. Assigning the 31 P signals as low field ( syn ) and high field ( anti ) shows an increasing tendency toward the anti isomer across the series Pd 2 Cl 4 ( 1 ) 2 –Pd 2 Cl 4 ( 3 ) 2 , consistent with greater ligand steric demand.…”

CuH-Catalyzed Regio- and Enantioselective Hydrocarboxylation of Allenes: Toward Carboxylic Acids with Acyclic Quaternary Centers

“…As an alternative, the hydrocarboxylation − of prochiral unsaturated substrates represents a straightforward approach for preparing carboxylic acids. Asymmetric hydrocarboxylation has typically , been achieved through palladium-catalyzed hydroxy- and alkoxycarbonylation processes using CO gas or a carbon monoxide surrogate. − Despite significant advances in this area, the vast majority of the methods can only synthesize α-tertiary acids or esters from vinyl arenes, and a highly enantioselective technique for the assembly of α-quaternary carboxylic acids through a hydrocarboxylation or hydroesterification of unsaturated substrates is still unknown …”

Tetra- and Dinuclear Palladium Complexes Based on a Ligand of 2,8-Di-2-pyridinylanthyridine: Preparation, Characterization, and Catalytic Activity

“…Owing to the remarkable activity of palladium ions in catalysis, the study of dipalladium-catalyzed reaction becomes an interesting task and receives much attention. Quite a few dipalladium complexes are known to show the catalytic activities in cross-coupling, , olefin polymerization, C–H activation/addition, hydroxycarbonylation, and reduction . An important feature of these dinuclear catalysts is that the metal ions are accommodated by a designed ligand, allowing them to be arranged in a close proximity.…”