Pd Catalyst System Research Articles

Palladium-catalyzed hydroesterification of alkynes in the presence of p-toluenesulfonic acid under a normal pressure of carbon monoxide

Hydroesterification of terminal alkynes with butanol proceeds smoothly and efficiently under a normal pressure of carbon monoxide by using a catalyst system of Pd(dba) 2/PPh 3/TsOH (dba=dibenzylideneacetone, TSOH = p-toluenesulfonic acid) to give the corresponding 2-substituted 2-propenoic acid butyl esters in good selectivity and yield. Internal alkynes can also be hydroesterified under similar conditions.

Palladium(II) catalysts for living alternating copolymerization of olefins and carbon monoxide

Several Pd(II) catalyst systems have been reported which effect prefectly alternating copolymerization of olefins with carbon monoxide to yield polyketones [C(O)CH(R)CH{sub 2}]{sub n}. There has been increasing interest in these polymers, particularly the C{sub 2}H{sub 4}/CO copolymer (T{sub m} = 257{degree}C), due to their unusual properties, the low cost of monomers, the present of the carbonyl functionality, and the potential for further functionalization. The catalyst systems used have typically employed Pd(II) salts in methanol or chloroform. We report here the synthesis of well-defined Pd(II) catalysts that operate in aprotic solvents to yield living alternating copolymers of olefins and CO. In situ spectroscopic studies have established mechanistic details including the identity of the catalyst resting state.

Oxidative carbonylation of styrene to ethyl cinnamate

A detailed study was made of the products of oxidative carbonylation of styrene in the presence of the catalyst system PdCl 2 -CuCl 2 -Cu(OAc) 2 -Mn(OAC) 2 at 100°C and 3.2 MPa. The target product, ethyl cinnamate, reached a molar proportion of 95%. The principal side reaction products were acetophenone and diethylphenyl succinate. Investigation of the influence of the composition of the catalyst system on the yield of target product and the selectivity of the reaction showed that Mn(OAc) 2 was of greatest importance as a co-catalyst in the multicomponent Pd catalyst system. The results are discussed with reference to an alcoholate mechanism for oxidative carbonylation of olefins.

ChemInform Abstract: Asymmetric Allylic Amination Catalyzed by Chiral Ferrocenylphosphine‐Palladium Complexes.

AbstractThe E‐configurated allylic carbonate (I) reacts with the amines (II) in the presence of an optically active Pd catalyst system to give the rearranged allylamines (III), together with minor amounts of the isomers (IV).

Selective conversion of nitrobenzene to phenylcarbamates catalyzed by Pd(II) and heteropolyacids

A homogeneous catalyst system of Pd(ll) and a heteropolyacid (HPA) converts nitrobenzene to N-phenylcarbamate with a selectivity of 96.3% at 100% nitrobenzene conversion, which appears to be the best value known in the literature. However, the catalyst forms solid deposits during the reaction.

Zur Telomerisierung von Isopren mit Palladium‐Komplexen bei niedriger Temperatur

On the Telomerization of Isoprene at Low TemperatureThe telomerization of isoprene was carried out by means of a catalyst system of Pd(acac)2/PPh3 and complexes of the type Pd(acac)2 · L (L = PPh3; py; NHEt2) at 298 K. The reaction in methanol gave 8‐methoxy‐2, 7‐dimethyl‐octa‐1, 6‐diene (3a), 8‐methoxy‐3, 7‐dimethyl‐octa‐1, 6‐diene (4a) and oligomer products. 2, 7‐Dimethyl‐octa‐1,3, 7‐triene (1), 8‐i‐propoxy‐2, 7‐dimethyl‐octa‐1, 6‐diene (3b) and oligomer products were obtained in i‐PrOH. During the reaction a formation phase of the catalyst was observed.