Keele Research Repository

Some substituted azonia-azulenes have been prepared for the first time. The synthetic route involves the
double elimination of hydrogen bromide from the appropriate a,a-dibromoketone using lithium chloride in dimethylformamide. Attempts have been made to synthesise the unsubstituted azonia­azulenes from the intermediate azepinones but these were not successful.
A brief review is given of the uses of lithium halides in dimethylformamide as reagents for elimination.
The double dehydrobromination reaction has been extended to give a new synthesis of benzo[2,3]tropones and related systems. Investigations into the mechanism of elimination have been carried out and a possible reaction pathway proposed.