Bromination of ferrocene chalcone derivatives mediated by β-cyclodextrin

Bromination of the inclusion complex of trans-ferrocenylchalcone derivatives with β-cyclodextrin was studied. In the absence of β-cyclodextrin, the analogous ferrocenylchalcone does not undergo bromination at room temperature, but its inclusion complex in β-cyclodextrin brominates smoothly and gives the erythro-dibromide derivatives. This complexation does not induce any variation in the bromination pattern and the ferrocenyl moiety is not attacked in the reaction. These observations have been accounted for in terms of guest-host interaction patterns. The formation of complex and dibromination product has been confirmed by elemental analyses, IR, ¹H-NMR, ¹³C-NMR, UV-Vis and electrochemical methods.