Nucleophilic reactivity of 4-functionalized cycloheptatrienones

Abstract

Replacement of either halogens or the tosyloxy-group from the troponoidal γ-carbon by dimethylamine occurs without rearrangement. Iodine and bromine are replaced in dimethyl sulphoxide as solvent much faster (the more so the higher is the amine concentration) than either the tosyloxy-group or chlorine, whereas the methoxy-group resists replacement. The relatively high reactivity of the iodo-compound is due to a lack of activation enthalpy–activation entropy compensation.