853200-99-4Relevant academic research and scientific papers
Methoxycarbonylation of styrene to methyl arylpropanoates catalyzed by palladium(II) precursors with 1,1′-bis(diphenylphosphino)metallocenes
Bianchini, Claudio,Meli, Andrea,Oberhauser, Werner,Parisel, Sebastien,Gusev, Oleg V.,Kal'sin, Alexander M.,Vologdin, Nikolai V.,Dolgushin, Fedor M.
, p. 35 - 49 (2008/10/09)
Palladium(II) complexes with 1,1′-bis(diphenylphosphino)ferrocene (dppf), 1,1′-bis(diphenylphosphino)octamethylferrocene (dppomf), 1,1′-bis(diphenylphosphino)ruthenocene (dppr) and 1,1′- bis(diphenylphosphino)osmocene (dppo) have been synthesized and used to catalyze the methoxycarbonylation of styrene. Irrespective of the precursor, all the reactions gave methyl phenylpropanoates with prevalence of the linear isomer methyl 3-phenylpropanoate (up to 85% regioselectivity). The highest turnover frequency was obtained with the dppr precursor in the presence of p-toluenesulphonic acid co-catalyst (334 mol of styrene converted (mol of catalyst h)-1). A reaction mechanism accounting for both activity and selectivity has been proposed on the basis of operando high-pressure NMR experiments and reactions with model compounds. The selective methoxycarbonylation of styrene to methyl phenylpropanoates, with large prevalence of the linear regioisomer, can be achieved by 1,1′- bis(diphenylphosphino)metallocenyl palladium(II) catalysts. The presence of methyl substituents on the cyclopentadienyl ligands, and the type of metal in the metallocenyl unit, which may vary from iron to ruthenium to osmium, control the catalytic activity.
