Triethylsilane → 5-Bromo-2,2-dimethyl-2,3-dihydro-1H-indene

6-Bromo-2,2-dimethyl-indan-1-one 45a (7.23 g, 30.3 mmol) was dissolved in 150 mL of trifluoroacetic acid followed by addition of triethylsilane (12.1 mL, 75.6 mmol). The reaction mixture was stirred overnight at room temperature. The reaction was monitored by TLC until the disappearance of the starting materials and then quenched by addition of water. The mixture was concentrated under reduced pressure to remove trifluoroacetic acid. The mixture was adjusted to be basic with saturated aqueous sodium bicarbonate and then extracted with ethyl acetate (50 mL×3). The combined organic extracts were washed with saturated brine, dried over anhydrous sodium sulfate, filtered to remove the drying agent and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain the title compound 5-bromo-2,2-dimethyl-indan 45b (14 g) as a colourless oil, which was directly used in the next step.