Friedel-Crafts alkylation of ferrocene with Z-cyclooctene and cyclohexene

Cycloalkylated ferrocene derivatives, potentially useful as liquid burning rate modifiers for the HTPB/AP-based composite rocket propellants, were synthesized by the Friedel-Crafts alkylation of ferrocene with Z-cyclooctene or cyclohexene in the presence of AlCl3 as a Lewis acid catalyst. The reaction with Z-cyclooctene yields a mixture of main products containing up to four C8H15 substituents, each of which exists in several isomeric forms, as recognized by MS and GC-MS techniques. Two isomeric monosubstituted products, cyclooctylferrocene and (1-methylcycloheptyl)ferrocene, isolated by means of preparative GC, were identified by C-13-NMR spectroscopy. In the case of cyclohexene, cyclohexylferrocene and a 2:1 mixture of 1,1'-dicyclohexylferrocene and 1,3-dicyclohexylferrocene were isolated and identified by MS and C-13-NMR spectroscopy. (C) 1999 Elsevier Science S.A. All rights reserved.