Methoxycarbonylation of styrene to methyl arylpropanoates catalyzed by palladium(II) precursors with 1,1′-bis(diphenylphosphino)metallocenes

✍ Scribed by Claudio Bianchini; Andrea Meli; Werner Oberhauser; Sebastien Parisel; Oleg V. Gusev; Alexander M. Kal'sin; Nikolai V. Vologdin; Fedor M. Dolgushin

• Book ID: 104056749
• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 546 KB
• Volume: 224
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/j.molcata.2004.06.029

✦ Synopsis

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.