General procedure for the synthesis of 2-bromo-2,3-dihydro-1H-indene from 2-bromoindanone: In a 250 mL dry three-necked flask, 22.0 g of 2-bromoindanone (bromo compound I) and 0.67 g of 5% palladium carbon catalyst were added. Subsequently, 250 mL of ethanol was added as solvent and the reaction was carried out under hydrogen atmosphere. The reaction pressure was maintained at 2.5 MPa and the molar ratio of 2-bromoindanone to hydrogen was 1:50. The reaction was carried out at room temperature with stirring for 24 hours. Upon completion of the reaction, the palladium carbon catalyst was recovered by filtration and the solvent was removed by rotary evaporation. Finally 18.5 g of 2-bromo-2,3-dihydro-1H-indene (Compound II) was obtained as an oil in 90% yield.
