Methoxycarbonylation of Styrene Catalyzed by Palladium Complexes with Ferrocene Derivatives Containing Nitrogen and Phosphine Ligands

Abstract

The catalytic behaviour of different complexes of Palladium(II) containing mono or bidentate phosphorus or nitrogen ligands in the methoxycarbonylation reaction is examined. The pre-catalysts containing either a diphosphine ligand possessing a ferrocenyl backbone or a naphthyridine ligand attached to the same ferrocenyl backbone showed different catalytic activity for the reaction. Complexes containing the 1,1-bis(diphenylphosphino)ferrocene (dppf) ligand showed a better catalytic activity than the complex having the naphthyridine ligand in its structure. Various effects of the addition of triphenylphosphine to these pre-catalysts were observed. More than 99% conversion was achieved in the methoxycarbonylation of styrene using Pd(II) catalysts with ferrocenyl chelate derivatives, mostly with the Pd(dppf)Cl 2 , [Pd(dppf)(Me-CN) 2 ](BF 4 ) 2 and [Pd(dppf)PPh 3 ](BF 4 ) 2 complexes without the presence of triphenylphosphine as is usual in this reaction. The reactions were carried out under mild pressure and temperature conditions.

Structural and theoretical studies of the methoxycarbonylation of higher olefins catalysed by (Pyrazolyl‐ethyl)pyridine palladium (II) complexes

“…First to be studied was the effect of acid promoters using inorganic, organic and Lewis acids (Table , entries 1–6). The role of the acid promoter in the methoxycarbonylaion reaction is believed to be the generation of the Pd‐hydride, considered as the active species . The most reactive acid was HCl (91%), while the organic acids, methyl sulfonic (MSA) and para‐tolylsulfonic ( p ‐TsOH) were inactive.…”

Cooperative Effects in Multimetallic Complexes Applied in Catalysis

“…For [(dtbpf)Pd(C 6 H 4 À 4À CN)X] (X = Br, OÀ C 6 H 4 À 4À OMe, OÀ C 6 H 3 À 3,5À (t-Bu) 2 ) it was shown that in nonpolar solvents the complexes exist as k 2 -tetracoordinated species, partial reversible dissociation occurs in polar solvents like THF and chloro- form to give the corresponding [(dtbpf)Pd(C 6 H 4 À 4À CN)][X] compounds. [119] The activity of k 3 -Pd compounds in catalysis has been investigated in the fields of methoxycarbonylation of styrene [120] and ethene [121] , copolymerization of carbon monoxide with ethene [122] , as well as α-arylation of ketones [118,123] . When [(dtbpf) Pd(PPh 3 )] 2 + was used in the methoxycarbonylation of styrene it showed shorter reaction times than its related complexes [(dtbpf)PdCl 2 ] and [(dtbpf)Pd(MeCN) 2 ] 2 + , which might hint at an influence of the k 3 -coordination mode on subsequent reactivity.…”

“…The hydroamination proceeds roughly two-fold faster with the in-situ oxidized catalysts than with its reduced form. [152a] A recently developed zirconium(IV) complex based on an OSSO-functionalized tetradentate ferrocene ligand (120) showed a change in selectivity between oxidized and reduced species. [157] While the reduced molecule catalyzes intramolecular addition of primary aminoalkenes, the oxidized does so for secondary aminoalkenes (Figure 20).…”

Methoxycarbonylation of Styrene by Palladium(ii) Complex Containing the Diphenylphosphinocyrhetrene Ligand

“…Increasing the amount of triphenylphosphine increase the conversion but a noticeably decrease on the regioselectivity is observed (entries 5-7), probably the excess of PPh 3 displace the metalloligand forming Pd(PPh 3 ) 2 Cl 2 as the catalytic specie, which is known to catalyze the metoxycarbonylation of styrene in moderate conversion and regioselectivity 13 (entry 12-13). To prove the above assumption we evaluate the catalytic properties of Pd(PPh 3 ) 2 Cl 2 under the same experimental conditions (entry 12).…”

“…[3][4][5][6][7] Several chelating diphosphines have been extensively studied, particularly interesting are those containing metallocenic fragments, for instance, palladium(II) complexes with 1,1-bis(diphenylphosphino)ferrocene (dppf), 1,1-bis(diphenylphosphino) octamethylferrocene (dppomf), 1,1-bis(diphenyl-phosphino)ruthenocene (dppr), and bis(diphenylphosphino)osmocene (dppo) have proven to catalyze the methoxycarbonylation of ethylene and styrene, showing high selectivity to the linear ester. [8][9][10][11][12][13] Gusev et. al.…”