[CH:1](NC(C)C)(C)C.[Li]CCCC.[F:13][C:14]([F:27])([F:26])[O:15][C:16]1[CH:17]=[C:18]([CH2:22][C:23]([OH:25])=[O:24])[CH:19]=[CH:20][CH:21]=1.CI>O1CCCC1.CCCCCC.O>[F:13][C:14]([F:26])([F:27])[O:15][C:16]1[CH:17]=[C:18]([CH:22]([CH3:1])[C:23]([OH:25])=[O:24])[CH:19]=[CH:20][CH:21]=1A solution of diisopropylamine (3.1 ml) in tetrahydrofuran (30 ml) was cooled to 0° C. before dropwise addition of 1.6M nBuLi in hexane (13.5 ml) and then stirred for 15 minutes and cooled to −70° C. 3-(trifluoromethoxy)-phenylacetic acid (2 g) was dissolved in tetrahydrofuran (20 ml) and added dropwise to the reaction mixture which was then allowed to warm to 0° C., stirred for 30 minutes and then cooled back to −70° C. Methyl iodide (0.9 ml) was then added slowly and the solution stirred for further 1.5 hours at −70° C. Water was added the solution washed with diethyl ether, the aqueous phase was acidified by addition of 25% aqueous HCl and then extracted twice with diethyl ether, dried over Mg2SO4, filtered and concentrated. The residue was purified by flash column chromatography (SiO2; hexane/EtOAc 3:1) to afford 2-(3-trifluoromethoxy-phenyl)-propionic acid (1.5 g) as a light yellow oil. MS (ISP): 232.9 ([M−H]+)).
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