At −78° C., lithium bis(trimethylsilyl)amide (1.0 M in THF) (3.6 mL, 3.6 mmol) was added slowly to a solution of methyl 2-(trimethylsilyl)acetate (0.59 mL, 3.6 mmol) in THF (20 mL). The mixture was maintained at −78° C. for 7 minutes and then 6-(benzyloxy)-2,2-dimethyl-2,3-dihydroinden-1-one (8.3) (0.535 g, 2.0 mmol) was added in one portion. The resulting mixture was stirred at −78° C. and allowed to warm to room temperature overnight. The reaction mixture was then diluted with EtOAc (200 mL), washed with water and brine, and dried over anhydrous sodium sulfate. After removing solvent, the residue was purified by chromatography (silica gel, 1:5 EtOAc/hexane) to give product 8.4 in 45% yield.
