Diisopropylamine (44.8 mL, 320 mmol) in THF (125 mL) was cooled to -15° C. n-Butyllithium (1.6 M, 200 mL, 320 mmol) was added over 20 minutes. The solution was cooled to -40° C. and stirred for 20 minutes. Tert-butyl acetate (43 mL, 320 mmol) in THF (90 mL) was added over 30 minutes and the reaction stirred for 30 minutes at -40° C. 1-(4-Benzyloxy-phenyl)-4-methyl-pentan-3-one (21.0 g, 100 mmol) from Example F in THF (125 mL) was added over 10 minutes and the reaction was stirred at -40° C. for 5 minutes. Acetic acid (40 mL, 700 mmol) was added and the reaction warmed to room temperature. The reaction was stripped to dryness and the product was partitioned between ethyl acetate and saturated NH4Cl. The organic layer was washed with water, 5% NaHCO3 and brine. It was dried (MgSO4) and concentrated to give the title compound.
