Palladium-Catalyzed Hydroesterification Research Articles

Catalytic hydroesterification of lignin: a versatile and efficient entry into fully biobased tunable materials

Hydroxyl groups of several industrial grade lignins are esterified by palladium-catalyzed hydroesterification reactions with CO and olefins, fatty esters or 1,3-butadiene.

Ligand-enabled palladium-catalyzed hydroesterification of vinyl arenes with high linear selectivity to access 3-arylpropanoate esters.

Palladium-catalyzed linear-selective hydroesterification of vinyl arenes with alcohols enabled by diphosphine ligands derived from bis[2-(diphenylphosphino)ethyl]amides has been developed. A variety of 3-arylpropanoate esters were obtained in high yields and regioselectivity. The robustness of this methodology was further demonstrated by the efficient gram-scale synthesis of the ethyl 3-phenylpropanoate as a precursor to hydrocinnamic acid.

Asymmetric Synthesis of 4-Aryl-3,4-dihydrocoumarins by Palladium-Catalyzed Hydroesterification

Key words palladium catalysis - dihydrocoumarins - carbon monoxide

Mechanistic Study of Palladium-Catalyzed Hydroesterificative Copolymerization of Vinyl Benzyl Alcohol and CO

The copolymerization of vinyl benzyl alcohol (VBA) and carbon monoxide (CO) to give a new polyester poly(VBA-CO) has been achieved via palladium-catalyzed hydroesterification. Reaction conditions i...

Regio- and Enantioselective Palladium-Catalyzed Hydroesterification

Key words palladium - hydroesterification - aryl alkenes - phenyl formate

Palladium-Catalyzed Asymmetric Hydroesterification of Alkenylphenols

Palladium-Catalyzed Asymmetric Hydroesterification of Alkenylphenols

Palladium-catalyzed hydroesterification of olefins with isosorbide in standard and Brønsted acidic ionic liquids

The palladium catalyzed hydroesterification of 1-octene with isosorbide was studied in standard and Brønsted acidic ionic liquids as reaction media. High conversions and selectivities towards the targeted isosorbide diesters have been achieved by using a catalytic system composed of Pd(OAc)2 and trisulfonated triphenylphosphine dissolved in 1-(4-sulfonic acid)-butyl-3-methylimidazolium tosylate. The catalytic phase can be reused several times without any significant decrease in activity and selectivity.

Biphasic Palladium-Catalyzed Hydroesterification in a Polyol Phase: Selective Synthesis of Derived Monoesters.

The palladium-catalyzed hydroesterification reaction was performed with polyols and olefins in a liquid/liquid biphasic system composed of unreacted polyol on the one hand and apolar reaction products/organic solvents on the other hand. The palladium-based catalyst was immobilized in the polyol phase thanks to the use of cationic triarylphosphines possessing pendent protonated amino groups in the acidic reaction medium or to the sulfonated phosphine TPPTS (trisodium triphenylphosphine-3,3',3''-trisulfonate). Owing to the insolubility of the products in the catalytic phase, this approach allowed the synthesis of monoesters of polyols with high selectivities as well as the easy separation of the catalyst through simple decantation.

Synthesis of 1,4:3,6-dianhydrohexitols diesters from the palladium-catalyzed hydroesterification reaction.

The hydroesterification of alpha olefins has been used to synthesize diesters from bio-based secondary diols: isosorbide, isomannide, and isoidide. The reaction was promoted by 0.2% palladium catalyst generated in situ from palladium acetate/triphenylphosphine/para-toluene sulfonic acid. Optimized reaction conditions allowed the selective synthesis of the diesters with high yields and the reaction conditions could be scaled up to the synthesis of hundred grams of diesters from isosorbide and 1-octene with solvent-free conditions.

METHOXYCARBONYLATION OF STYRENE BY PALLADIUM(II) COMPLEX CONTAINING THE DIPHENYLPHOSPHINOCYRHETRENE LIGAND

ABSTRACT The palladium-catalyzed methoxycarbonylation of vinylarenes has been investigated for the first time using phosphinocyrhetrene [(η 5 -C 5 H 4 PPh 2 )Re(CO) 3 ] a non-metallocenic organometallic ligand. The catalytic system trans-[(η 5 -C 5 H 4 PPh 2 )Re(CO) 3 ]PdCl 2 (NCMe)/PPh 3 (1:2 ratio), carbon monoxide and methanol, in the presence of HCl as acidic promoter, showed good catalytic activity, excellent regioselectivity to the branched products and chemoselectivity up to 94%. Keywords: Methoxycarbonylation, phosphinocyrhetrene ligand, vinylarenes. 1.- INTRODUCTION Palladium-catalyzed hydroesterification reaction (Reppe carbonylation) is a powerful synthetic strategy for the preparation of linear and branched esters from easily available unsaturated substrates. 1,2 It has been established that the regioselectivity of carboxylation products is strongly dependent on the ligands bound to a transition metal and the reaction conditions. The most common catalytic system involve Pd(II) and mono- and bidentate aromatic phosphines. Catalysts containing bidentate diphosphine ligands have been more frequently used for this reaction, but they have the disadvantage to produce branched product in low regio- and enantioselectivity, although a few successful examples have been reported recently.

Electronic Effect of Diphosphines on the Regioselectivity of the Palladium-Catalyzed Hydroesterification of Styrene

The electronic character of the diphosphine ligands controls the regioselectivity of the Pd-catalyzed carbonylation of styrene. In the presence of electron-poor phosphines branched esters are produced and high activities of the catalytic systems are observed.

Palladium-catalyzed hydroesterification of styrene derivatives in the presence of ionic liquids

The palladium-catalyzed hydroesterification of olefins occurs efficiently in a range of ionic liquid media. Selectivities ranging from 5–7:1 for the linear ester were obtained with styrene in a range of IL solvents. The use of ILs allowed the catalyst to be easily separated from the organic product by either extraction or distillation. The (Ph 3P) 2PdCl 2 precatalyst could be recovered unchanged from the ionic liquid phase. The IL/catalyst phase could be recycled five times with an average yield of 68%.

Regioselective synthesis of 2-arylpropionic esters by palladium-catalyzed hydroesterification of styrene derivatives in molten salt media

The palladium-catalyzed hydroesterification of styrene derivatives is performed in a two-phase system composed of 1- n-butyl-3-methylimidazoliumtetrafluoroborate salt (ionic phase) and isopropanol/cyclohexane (organic phase). Very high regioselectivities in 2-arylpropionic esters (≥99.5%) are obtained using a catalytic system composed of PdCl 2(PhCN) 2, (+)-neomenthyldiphenylphosphine (NMDPP) and p-toluenesulfonic acid under mild reaction conditions (10 atm and 70°C).

Palladium-catalyzed hydroesterification of propene into methyl 2-methylpropanoate at room temperature and atmospheric pressure. Influence of various parameters on the activity and selectivity of the reaction

The hydroesterification of propene into methyl 2-methylpropanoate by homogeneous catalytic systems consisting of palladium, copper, oxygen and acid is investigated under very mild conditions (room temperature, atmospheric pressure). From experimental results it appears that: (i) very high selectivities (up to 95%) into the branched ester can be obtained; (ii) the presence of CuCl2 and O2 as final reoxidant of palladium is required; (iii) the activity increases with partial pressure of O2 in the gas phase.

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-Catalyzed Hydroesterification of Alkenes in the Presence of Molecular Hydrogen

The effects of molecular hydrogen on the palladium-catalyzed alkene-alcohol-carbon monoxide and alkene-formate reactions have been studied. Yields of esters were generally increased, especially in the alkene-formate reaction, in which an improvement up to 46% yield has been observed. A possible explanation is proposed in which the molecular hydrogen promotes the oxidative addition of formate to palladium. Decarbonylation of formate ester is unlikely to be the initial step.