Short and Selective Synthesis of 3,5-dibromoinden-1-one

Brominations of hydrocarbons are important processes in synthetic chemistry. Bromoindanes and bromoindenones are key intermediate for medicinally valuable compounds. Short and efficient synthesis of 3,5-dibromoinden-1-one is presented. 5-bromoindane-1-one 1 was treated with ethylene glycol to mask the ketone functional group to yield the cyclic ketal 2. Bromination of bromoindanecyclic ketal 2 with bromine in photochemical reaction apparatus while being irradiated with a projector lamp afforded the product which was treated with silica gel directly to remove the protective group afforded the corresponding 3,5-dibromoinden-1-one 3.