[C:1]([C:5]1[CH:10]=[C:9]([F:11])[CH:8]=[C:7]([CH:12]([O:15][CH3:16])[O:13][CH3:14])[CH:6]=1)([CH3:4])([CH3:3])[CH3:2].[C:17](=[O:19])=[O:18].Cl>C1COCC1>[C:1]([C:5]1[CH:10]=[C:9]([F:11])[C:8]([C:17]([OH:19])=[O:18])=[C:7]([CH:12]([O:13][CH3:14])[O:15][CH3:16])[CH:6]=1)([CH3:4])([CH3:2])[CH3:3]1-tert-Butyl-3-dimethoxymethyl-5-fluoro-benzene (333 g, 1.47 moles) was dissolved in THF (10 vol, 3.3 L) and cooled to −70° C. secBuLi (1.4M in cyclohexanes, 1.0 eq, 1000 mL) was added drop-wise over 1.5 hours. The solution was stirred at −70° C. for one hour and then CO2 gas was added to the reaction via a sintered glass gas dispersion tube, while maintaining vigorous stirring. The reaction was allowed to warm with vigorous stirring with adequate venting for release of excess CO2 from the solution. Once the internal temperature had reached +10° C. the reaction was quenched with water (3 L) followed by conc. HCl (1.15 eq, 140 mL). The aqueous fraction was extracted to ethyl acetate (1 L) and the combined organic fractions were combined and washed with water (2×1 L), and then concentrated with solvent replacement with heptanes. The resulting fine crystals were filtered, washed with heptanes and then dried at room temperature under vacuum with N2 sweep to provide 220.3 g (55.3%).
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