Date of Original Version
The effects of oxidant and organic acid additives on the oxidative cross-coupling reactions of electron rich heterocycles such as benzofuran with benzene were studied. Both regioselectivity and reaction rate could be controlled by varying the condition parameters. Furthermore, mechanistic insight was achieved via kinetic studies which indicate that reactions that are oxidized by the heteropoly acid H4PMo11VO40 operate via a Pd(II)/Pd(IV) mechanisms, while reactions oxidized by either AgOAc or Cu(OAc)2 operate by a Pd(II)/Pd(0) mechanism.
Kyle C. Pereira, Ashley L. Porter, Shathaverdhan Potavathri, Alexis P. LeBris, Brenton DeBoef, Insight into the palladium-catalyzed oxidative arylation of benzofuran: heteropoly acid oxidants evoke a Pd(II)/Pd(IV) mechanism, Tetrahedron, Volume 69, Issue 22, 3 June 2013, Pages 4429-4435, ISSN 0040-4020, http://dx.doi.org/10.1016/j.tet.2013.02.061.