Promoting Effect of AlCl3 on the Fe-catalyzed Dimerization of Bicyclo[2.2.1]hepta-2,5-diene

The activity of the catalytic system composed of Fe(acetylacetonate)3 (Fe(acac)3), triphenylphosphine, and diethylaluminum chloride for the dimerization of bicyclo[2.2.1]hepta-2,5-diene (2,5-norbornadiene, NBD) to produce hexacyclic endo-endo dimer (hexacyclo[7.2.1.02,8.13,7.15,13.04,6]tetradec-10-ene, Hnn) was significantly enhanced by the presence of AlCl3, especially at the molar ratios of NBD/Fe(acac)3 of 500. XPS analysis of the catalytic systems clearly demonstrates that AlCl3 facilitates the reduction of Fe(acac)3 to form active species, Fe(II) and Fe(0) species. The layer separation was observed when [BMIm]Cl was used along with AlCl3, but catalyst recycle was not very successful. KCI Citation Count: 7