86994-29-8

Upstream product

• 620632-34-0 trans-[Pd2(μ-Cl)2(CH(C6F5)CH2CO2Me)2(tetrahydrothiophene)2] 
• 620632-33-9 trans-[Pd2(μ-Cl)2(CH(CO2Me)CH2C6F5)2(tetrahydrothiophene)2] 
• 67-56-1 methanol 
• 653-34-9 2,3,4,5,6-pentafluorostyrene 
• 201230-82-2 carbon monoxide 
• 125475-73-2 trans-[Pd(C₆F₅)Br(CH₃CN)2] 
• 292638-85-8 acrylic acid methyl ester 

Relevant academic research and scientific papers

A general platinum-catalyzed alkoxycarbonylation of olefins

Hydroxy- and alkoxycarbonylation reactions constitute important industrial processes in homogeneous catalysis. Nowadays, palladium complexes constitute state-of-the-art catalysts for these transformations. Herein, we report the first efficient platinum-catalysed alkoxycarbonylations of olefins including sterically hindered and functionalized ones. This atom-efficient catalytic transformation provides straightforward access to a variety of valuable esters in good to excellent yields and often with high selectivities. In kinetic experiments the activities of Pd- and Pt-based catalysts were compared. Even at low catalyst loading, Pt shows high catalytic activity.

Polymerization of acrylates by neutral palladium complexes. Isolation of complexes at the initial steps

The polymerization of methyl acrylate by pentafluorophenyl complexes [Pd2(μ-X)2(C6F5)2 L2] (L = tetrahydrothiophene (tht), X = Cl, 2; L = tht, X = Br, 3; L = AsPh3, X = Br, 4) gives atactic polymers in good yields. Mechanistic studies reveal that the polymerization of methyl acrylate starts by insertion of methyl acrylate in the Pd-aryl bond of the precatalyst to give the alkyl complexes trans-[Pd2(μ-Cl)2{CH(CO2Me) -CH2C6F5}2 (tht)2] (5) and trans-[Pd2-(μ-Cl)2{CH(C6F5) CH2CO2Me}2 (tht)2] (6). These complexes can be isolated, and the X-ray crystal structure of 5 has been determined. Complexes 5 and 6 decompose mainly by β-H elimination but also by homolytic cleavage of the Pd-C bond in the light. In the presence of methyl acrylate, insertion of MA in hydrido-Pd species produces the alkyl complex trans-[Pd2(μ-Cl)2{CH(CO2Me) CH3}2(tht)2] (9). Then a radical polymerization is initiated by small amounts of the radicals generated from these complexes (5, 6, or 9). Formation of 9 is the regeneration pathway of radicals after a termination reaction has occurred by recombination of the growing radical with palladium and β-H elimination. The success of the polymerization requires a slow but steady supply of radicals by slow decomposition of alkyl complexes (5 and 6) or by slow generation of Pd-H species that provide new alkyl complexes (9), as well as an efficient recycling of the Pd-H generated in the termination step to 9.

Palladium-based system for the polymerization of acrylates. Scope and mechanism

The neutral palladium complex [Pd(C6F5)Br(NCMe)2] (1) was found to effect the polymerization of acrylates upon addition of 1 equiv of a monodentate phosphine or pyridine or an excess of halide. Methyl methacrylate was not polymerized, and furthermore, its addition stopped the progress of independently initiated methyl acrylate polymerization in the phosphine-based system. Addition of ethene also inhibited the polymerization of methyl acrylate. However, over 10 mol % incorporation of 1-hexene in the polymer was achieved when the latter was added together with methyl acrylate. The polymerizaion mechanism is discussed.