Pd-(MOP) Chemistry: Novel Bonding Modes and Interesting Charge Distribution

An Efficient Asymmetric Cross-Coupling Reaction in Aqueous Media Mediated by Chiral Chelating Mono Phosphane Atropisomeric Biaryl Ligand

The enantiomerically pure ligand BisNap-Phos was obtained in a straightforward sequence of reactions beginning with inexpensive starting materials under the readily affordable conditions in high overall yield. An asymmetric BisNap-Phos-palladium complex-catalyzed Suzuki–Miyaura coupling leading to axially chiral biaryl compounds was described. The reactions were carried out under mild conditions in aqueous and organic media. A series of atropisomeric biaryls were synthesized with excellent yields and high enantioselectivities (up to 86% ee). The methodology provides an efficient and practical strategy for the synthesis of novel multifunctionalized axially chiral biaryl compounds under mild environmentally friendly and easily affordable conditions.

Fluxional chloro-pyrrole–Pd(ii) complex to cationic η2-pyrrole–Pd(ii) complex: subtlety in structure-directed bonding mode

The fluxional pyrrole ring of a Pd(ii) complex produces a η²-pyrrole–Pd(ii) complex. It is the first report of a η²-pyrrole complex of Pd(ii).

[Pd(acac)(MeCN)2]BF4: air-tolerant, activator-free catalyst for alkene dimerization and polymerization

[Pd(acac)(MeCN)₂]BF₄ has been observed to catalyze selective substituted styrene dimerization and addition norbornene polymerization.

Cyclic enolates of Ni and Pd: equilibrium between C- and O-bound tautomers and reactivity studies

2-acylaryl complexes of Ni and Pd containing chelating diphosphines react with KtBuO to give metallacyclic enolate complexes. While coordination through the carbon atom is preferred in the case of Pd, the nickel O-enolate compounds are formed as the corresponding O-tautomers. Slow equilibration between O- and C-enolate tautomers is observed for the nickel complex with an unsubstituted enolate function (M-O-C=CH(2)). Theoretical DFT calculations suggest that the barrier for the tautomer exchange has its origin in the rigidity of the metallacycle. Whilst the C-enolate tautomer is unreactive towards aldehydes, the corresponding O-enolate adds to MeCHO and PhCHO, giving rise to products that retain the enolate functionality. The carbonylation of these products cleanly leads to the formation of enol lactones in a highly selective manner.

Dibenzo[a,d]cycloheptenyl dibenzophosphole palladium dichloride: synthesis, X-ray-crystal structure and application in the Suzuki-Miyaura coupling

A highly rigid dibenzo[a,d]cycloheptenyl dibenzophosphole with a pre-organized concave shaped binding site acts as an efficient ligand in the palladium catalyzed Suzuki-Miyaura coupling process between halogenoaromatics and phenylboronic acid.

Synthesis, structure and dynamics of methoxynaphthalene-substituted phospha-ruthenocenes and -ferrocenes

The syntheses of potassium 2-(2'-methoxynaphth-1'-yl)-3,4-dimethyl-5-phenylphospholide 4 and eta5-pentamethylcyclopentadienyl(eta5-2-(2-methoxynaphth-1-yl)-3,4-dimethyl-5-phenylphospholyl)-ruthenium(II)5 and -iron(II)6 are described. The barrier to rotation of the naphthyl group (79 kJ mol-1 and 72 kJ mol-1 in CD2Cl2 respectively) characterises 5 and 6 as potential tropos type ligands. Coordination of 5 to [PtCl2(PEt3)] gives two cis and two trans complexes [PtCl2(PEt3)5] wherein rotation about the phospholyl-naphthyl vector is slow.