[CH3:1][O:2][C:3]([CH:5]1[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][C:13]=2[O:15][CH3:16])[CH2:8][CH2:7][C:6]1=[O:17])=[O:4].[Li+].[CH3:19][CH:20]([N-]C(C)C)[CH3:21].C(Br)C=C>C1COCC1>[CH3:1][O:2][C:3]([CH:5]1[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][C:13]=2[O:15][CH3:16])[CH2:8][CH:7]([CH2:21][CH:20]=[CH2:19])[C:6]1=[O:17])=[O:4]A solution of 10.2 g (43.5 mmol) 1,2,3,4-tetrahydro-8-methoxy-2-oxo-1-naphthalene carboxylic acid methyl ester in 108 mL of THF in a three-neck, round-bottomed flask, equipped with a dropping funnel, was added dropwise 63.8 mL (95.7 mmol) of LDA (1.5 M in cyclohexane) at −30° C. to −40° C. under a nitrogen atmosphere. The solution was allowed to warm to 0° C. and 6.0 mL (69.6 mmol) of allylbromide was added. After stirring the mixture for one hour at room temperature, TLC analysis showed no starting material remaining. The reaction was quenched with 3N hydrochloric acid to pH 2-3 and extracted with ethyl acetate (2×1 L). The combined organic layers were washed with brine, dried (MgSO4), filtered, and concentrated in vacuo. The resulting oil was purified by liquid chromatography on 800 g silica gel 60 (230-400 m), eluting with hexane-acetone (3: 1), and collecting 40 mL fractions. Fractions 36-63 gave 10.3 g (87%) of pure title compound as a yellow oil.
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