869966-86-9Relevant academic research and scientific papers
Role of the ligand and of the size and flexibility of the palladium-ancillary ligand cycle on the reactivity of substituted alkynes toward palladium(0) complexes bearing potentially terdentate nitrogen-sulfur-nitrogen or nitrogen-nitrogen-nitrogen ligands
Canovese, Luciano,Visentin, Fabiano,Chessa, Gavino,Uguagliati, Paolo,Levi, Carlo,Dolmella, Alessandro,Bandoli, Giuliano
, p. 5355 - 5365 (2008/10/09)
The reaction between palladium(0) complexes bearing potentially terdentate ligands and dimethyl acetylenedicarboxylate (DMA) to give the corresponding palladacyclopentadiene complexes was studied under kinetic conditions. The reactivity of the complexes w
Attack of substituted alkynes on olefin palladium(O) derivatives of pyridylthioethers. The first kinetic study on the mechanism of formation of palladacyclopentadiene complexes
Canovese, Luciano,Visentin, Fabiano,Chessa, Gavino,Uguagliati, Paolo,Levi, Carlo,Dolmella, Alessandro
, p. 5537 - 5548 (2008/10/09)
The formation of metallacyclopentadienyl derivatives was studied under controlled conditions, and the kinetics and mechanism of reactions between pyridylthioether olefin Pd(0) substrates and substituted alkynes of the type ZC=CZ (Z = COOMe, COOEt, COOt-Bu) leading to the corresponding palladacyclopentadienyl species were systematically investigated. In the case of less hindered ancillary ligands the attack of the alkyne forming a reactive monoalkyne intermediate was found to be the rate-determining step. In this respect the rates of reaction were discussed in terms of the substituent-induced basicity-of sulfur and nitrogen of the ancillary ligands. The associative nature of the attack was unequivocally established, and the formation of a transition state bearing a monodentate ancillary ligand was proposed. In the case of more hindered ancillary ligands a partially stabilized monoalkyne intermediate is formed irrespective of the olefin in the starting complex, and this species strongly influences the reaction progress. Formation of hexamethylmellitate under mild conditions is also observed.
