Oxidative arylation of ethylene with benzene catalyzed by Pd(OAc)2/heteropoly acid/O2 system

Abstract

Oxidative arylation of ethylene with benzene was examined by using a Pd(OAc)2/heteropoly acid/O2 system under mild conditions. The reaction of benzene with ethylene in the presence of catalytic amounts of Pd(OAc)2 combined with H4PMo11VO40·15H2O (or H3PMo12O40·30H2O), AcONa, and dibenzoylmethane under air at 90–120 °C produced oxidative coupling products, styrene and stilbene, in fair yields (up to 167 total turnovers). From the examination of the catalyst performance of Pd(OAc)2 combined with various heteropoly acids, it was found that the employment of heteropoly acids including molybdenum ion in their structure is very important to obtain high turnover numbers of Pd.